Remove duplication of table_compute_checksum function

It seems like there was some merge error when first cleaning up and
sharing this function.  We have both an inline version of the function
in include/tables_csum.h and a non-inline version in lib/tables_csum.c.
Rework things so that we only have the non-inline version (due to number
of calls, we should not inline this).

Fixes: 1befb38b86 ("x86: Move table csum into separate file")
Fixes: 2b445e4d31 ("x86: Move table csum into separate header")
Cc: Alexander Graf <agraf@csgraf.de>
Signed-off-by: Tom Rini <trini@konsulko.com>

arch/x86/include/asm/tables.h

@@ -16,19 +16,6 @@
 /* SeaBIOS expects coreboot tables at address range 0x0000-0x1000 */
 #define CB_TABLE_ADDR	0x800
 
-/**
- * table_compute_checksum() - Compute a table checksum
- *
- * This computes an 8-bit checksum for the configuration table.
- * All bytes in the configuration table, including checksum itself and
- * reserved bytes must add up to zero.
- *
- * @v:		configuration table base address
- * @len:	configuration table size
- * @return:	the 8-bit checksum
- */
-u8 table_compute_checksum(void *v, int len);
-
 /**
  * table_fill_string() - Fill a string with pad in the configuration table
  *