c6x: use common built-in dtb support

Using the common build support for built-in dtb files just requires
adding a .dtb.o target to obj-y.

The dtb now needs to be copied when unflattened because an init section
is used now.

Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <jacquiot.aurelien@gmail.com>
Cc: linux-c6x-dev@linux-c6x.org
Signed-off-by: Rob Herring <robh@kernel.org>

arch/c6x/kernel/setup.c

@@ -270,7 +270,7 @@ int __init c6x_add_memory(phys_addr_t start, unsigned long size)
 notrace void __init machine_init(unsigned long dt_ptr)
 {
 	void *dtb = __va(dt_ptr);
-	void *fdt = _fdt_start;
+	void *fdt = __dtb_start;
 
 	/* interrupts must be masked */
 	set_creg(IER, 2);
@@ -363,7 +363,7 @@ void __init setup_arch(char **cmdline_p)
 					 memory_end >> PAGE_SHIFT);
 	memblock_reserve(memory_start, bootmap_size);
 
-	unflatten_device_tree();
+	unflatten_and_copy_device_tree();
 
 	c6x_cache_init();
 

arch/c6x/kernel/vmlinux.lds.S

@@ -90,16 +90,6 @@ SECTIONS
 		*(.switch)
 	}
 
-	. = ALIGN (8) ;
-	__fdt_blob : AT(ADDR(__fdt_blob) - LOAD_OFFSET)
-	{
-		_fdt_start = . ;	/* place for fdt blob */
-		*(__fdt_blob) ;		/* Any link-placed DTB */
-		BYTE(0);		/* section always has contents */
-	        . = _fdt_start + 0x4000;	/* Pad up to 16kbyte */
-		_fdt_end = . ;
-	}
-
 	_etext = .;
 
 	/*