arch/x86: Increase MAX_SMBIOS_SIZE

With the recent addition of SMBIOS table 20, the cbmem area on
google/brya0 overflows and

ERROR: Increase SMBIOS size
SMBIOS tables: 2128 bytes.

is seen in the logs.

Therefore, double the size of the SMBIOS area from 2 KiB to 4 KiB to
accomodate more tables as needed. This happens during ramstage so 2k
is not a big deal at this point.

Change-Id: I43aa6a88d176e783cc9a4441b35b8d608c4101cd
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58432
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/arch/x86/tables.c

@@ -143,7 +143,7 @@ static unsigned long write_smbios_table(unsigned long rom_table_end)
 {
 	unsigned long high_table_pointer;
 
-#define MAX_SMBIOS_SIZE 2048
+#define MAX_SMBIOS_SIZE (4 * KiB)
 
 	high_table_pointer = (unsigned long)cbmem_add(CBMEM_ID_SMBIOS,
 		MAX_SMBIOS_SIZE);