xtensa: Correct define of _end symbol

So U-Boot is using _end symbol to detect location of devicetree
appended at the end of the ROM.

It needs to be calculated based on end of .data load address,
as in our lds .current address is address in RAM.

Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>

arch/xtensa/cpu/u-boot.lds

@@ -82,6 +82,8 @@ SECTIONS
 
   __reloc_end = .;
   __init_end = .;
+  /* Calculation to get end address in ROM */
+  _end = LOADADDR(.data) + (_data_end - _data_start);
 
   SECTION_bss(__init_end (OVERLAY),)
 

arch/xtensa/include/asm/ldscript.h

@@ -165,7 +165,6 @@
 		. = ALIGN(8);						\
 		_bss_end = ABSOLUTE(.);					\
 		__bss_end = ABSOLUTE(.);				\
-		_end = ALIGN(0x8);					\
 		PROVIDE(end = ALIGN(0x8));				\
 		_stack_sentry = ALIGN(0x8);				\
 	}