kconfig: include kernel/Kconfig.preempt from init/Kconfig

Almost all architectures include it.  Add a ARCH_NO_PREEMPT symbol to
disable preempt support for alpha, hexagon, non-coldfire m68k and
user mode Linux.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

arch/mips/Kconfig

@@ -2818,8 +2818,6 @@ config HZ
 config SCHED_HRTICK
 	def_bool HIGH_RES_TIMERS
 
-source "kernel/Kconfig.preempt"
-
 config KEXEC
 	bool "Kexec system call"
 	select KEXEC_CORE