docs: admin-guide: add kdump documentation into it

The Kdump documentation describes procedures with admins use
in order to solve issues on their systems.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/admin-guide/bug-hunting.rst

@@ -90,9 +90,9 @@ the disk is not available then you have three options:
     run a null modem to a second machine and capture the output there
     using your favourite communication program.  Minicom works well.
 
-(3) Use Kdump (see Documentation/kdump/kdump.rst),
+(3) Use Kdump (see Documentation/admin-guide/kdump/kdump.rst),
     extract the kernel ring buffer from old memory with using dmesg
-    gdbmacro in Documentation/kdump/gdbmacros.txt.
+    gdbmacro in Documentation/admin-guide/kdump/gdbmacros.txt.
 
 Finding the bug's location
 --------------------------

Documentation/admin-guide/index.rst

@@ -39,6 +39,7 @@ problems and bugs in particular.
    ramoops
    dynamic-debug-howto
    init
+   kdump/index
    perf/index
 
 This is the beginning of a section with information of interest to

Documentation/admin-guide/kdump/index.rst

@@ -1,4 +1,3 @@
-:orphan:
 
 ================================================================
 Documentation for Kdump - The kexec-based Crash Dumping Solution

Documentation/admin-guide/kernel-parameters.txt

@@ -708,14 +708,14 @@
 			[KNL, x86_64] select a region under 4G first, and
 			fall back to reserve region above 4G when '@offset'
 			hasn't been specified.
-			See Documentation/kdump/kdump.rst for further details.
+			See Documentation/admin-guide/kdump/kdump.rst for further details.
 
 	crashkernel=range1:size1[,range2:size2,...][@offset]
 			[KNL] Same as above, but depends on the memory
 			in the running system. The syntax of range is
 			start-[end] where start and end are both
 			a memory unit (amount[KMG]). See also
-			Documentation/kdump/kdump.rst for an example.
+			Documentation/admin-guide/kdump/kdump.rst for an example.
 
 	crashkernel=size[KMG],high
 			[KNL, x86_64] range could be above 4G. Allow kernel
@@ -1207,7 +1207,7 @@
 			Specifies physical address of start of kernel core
 			image elf header and optionally the size. Generally
 			kexec loader will pass this option to capture kernel.
-			See Documentation/kdump/kdump.rst for details.
+			See Documentation/admin-guide/kdump/kdump.rst for details.
 
 	enable_mtrr_cleanup [X86]
 			The kernel tries to adjust MTRR layout from continuous

Documentation/powerpc/firmware-assisted-dump.txt

@@ -59,7 +59,7 @@ as follows:
          the default calculated size. Use this option if default
          boot memory size is not sufficient for second kernel to
          boot successfully. For syntax of crashkernel= parameter,
-         refer to Documentation/kdump/kdump.rst. If any offset is
+         refer to Documentation/admin-guide/kdump/kdump.rst. If any offset is
          provided in crashkernel= parameter, it will be ignored
          as fadump uses a predefined offset to reserve memory
          for boot memory dump preservation in case of a crash.

Documentation/translations/zh_CN/oops-tracing.txt

@@ -53,8 +53,8 @@ cat /proc/kmsg > file， 然而你必须介入中止传输， kmsg是一个“
 （2）用串口终端启动（请参看Documentation/admin-guide/serial-console.rst），运行一个null
 modem到另一台机器并用你喜欢的通讯工具获取输出。Minicom工作地很好。
 
-（3）使用Kdump（请参看Documentation/kdump/kdump.rst），
-使用在Documentation/kdump/gdbmacros.txt中定义的dmesg gdb宏，从旧的内存中提取内核
+（3）使用Kdump（请参看Documentation/admin-guide/kdump/kdump.rst），
+使用在Documentation/admin-guide/kdump/gdbmacros.txt中定义的dmesg gdb宏，从旧的内存中提取内核
 环形缓冲区。
 
 完整信息