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 <[e-mail]>
Cc: Aurelien Jacquiot <[e-mail]>
Cc: [e-mail]
Signed-off-by: Rob Herring <[e-mail]>

arch/c6x/boot/dts/Makefile

···
 DTC_FLAGS ?= -p 1024
 
 ifneq ($(DTB),)
-obj-y += linked_dtb.o
+obj-y += $(DTB).dtb.o
 endif
-
-quiet_cmd_cp = CP      $< $@$2
-	cmd_cp = cat $< >$@$2 || (rm -f $@ && echo false)
-
-# Generate builtin.dtb from $(DTB).dtb
-$(obj)/builtin.dtb: $(obj)/$(DTB).dtb
-	$(call if_changed,cp)
-
-$(obj)/linked_dtb.o: $(obj)/builtin.dtb

arch/c6x/boot/dts/linked_dtb.S

···
-.section __fdt_blob,"a"
-.incbin "arch/c6x/boot/dts/builtin.dtb"

arch/c6x/include/asm/sections.h

···
 extern char _vectors_end[];
 
 extern char _data_lma[];
-extern char _fdt_start[], _fdt_end[];
 
 #endif /* _ASM_C6X_SECTIONS_H */

arch/c6x/kernel/setup.c

···
 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);
···
 					 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

···
 		*(.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 = .;
 
 	/*