SMBIOS: Introduce smbios_carve_table function

Factor out some boilerplate code into a helper `smbios_carve_table`
function, which zeroes out the table memory and fills in the header
fields common to all tables.

Change-Id: Iece2f64f9151d3c79813f6264dfb3a92d98c2035
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55907
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Michał Żygowski <michal.zygowski@3mdeb.com>

src/include/smbios.h

@@ -10,6 +10,8 @@ unsigned long smbios_write_tables(unsigned long start);
 int smbios_add_string(u8 *start, const char *str);
 int smbios_string_table_len(u8 *start);
 
+void *smbios_carve_table(unsigned long start, u8 type, u8 length, u16 handle);
+
 /* Used by mainboard to add an on-board device */
 enum misc_slot_type;
 enum misc_slot_length;