util/ifdtool/ifdtool.c: Add NULL check for fmapname

Some boards (e.g. prodrive/hermes) that do not provide their own FMAP
and therefore have been generated by the build system (+ ifdtool)
experience a failure when trying to build with an IFD that contains
regions which do not have equivalent fmap names (set to NULL).

Therefore add a NULL check for the fmapname and ignore the region if we
do not have an fmapname.

Test: compile prodrive/hermes

Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Change-Id: Ib4589b7fdbd11d644214ca5601536e9aeb26882f
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79010
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
diff --git a/util/ifdtool/ifdtool.c b/util/ifdtool/ifdtool.c
index ddbc0fb..43451b1 100644
--- a/util/ifdtool/ifdtool.c
+++ b/util/ifdtool/ifdtool.c
@@ -1068,6 +1068,14 @@
 		if (region.limit == 0 || region.base == 0x07FFF000)
 			continue;
 
+		/* Is there an FMAP equivalent? IFD reserved regions are usually thrown out
+		 * of the FMAP here
+		 */
+		if (!region_names[region.type].fmapname) {
+			printf("Skip IFD region: %s\n", region_names[region.type].pretty);
+			continue;
+		}
+
 		/* Here we decide to use the coreboot generated FMAP BIOS region, instead of
 		 * the one specified in the IFD. The case when IFD and FMAP BIOS region do not
 		 * match cannot be caught here, therefore one should still validate IFD and