libpayload: Add new memory type CB_MEM_TAG

Add new memory type CB_MEM_TAG to coreboot_tables.h. This definition was
missing when CB:90470 was instroduced.

Change-Id: I76990706649bc1a4e45478760446dff40e871d77
Signed-off-by: Yidi Lin <yidilin@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90612
Reviewed-by: Chen-Tsung Hsieh <chentsung@google.com>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

payloads/libpayload/include/coreboot_tables.h

@@ -121,6 +121,7 @@ struct cb_memory_range {
 #define CB_MEM_NVS          4
 #define CB_MEM_UNUSABLE     5
 #define CB_MEM_VENDOR_RSVD  6
+#define CB_MEM_TAG          7
 #define CB_MEM_TABLE       16
 
 struct cb_memory {