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>

drivers/misc/qfw.c

@@ -15,9 +15,6 @@
 #include <dm.h>
 #include <misc.h>
 #include <tables_csum.h>
-#ifdef CONFIG_GENERATE_ACPI_TABLE
-#include <asm/tables.h>
-#endif
 
 #if defined(CONFIG_GENERATE_ACPI_TABLE) && !defined(CONFIG_SANDBOX)
 /*