ich_descriptors: Use MAX_NUM_FLREGS for entries[]

5 regions made sense in 2013 when this bit of code was originally
written. MAX_NUM_FLREGS is now used to keep track of the max number of
flash regions and is >5 since Sunrise Point.

Change-Id: Idb559e618369fecf930724a7c1c84765247f3e38
Signed-off-by: David Hendricks <dhendricks@fb.com>
Reviewed-on: https://review.coreboot.org/21338
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

ich_descriptors.h

@@ -568,7 +568,7 @@ struct ich_descriptors {
 
 struct ich_layout {
 	struct flashrom_layout base;
-	struct romentry entries[5];
+	struct romentry entries[MAX_NUM_FLREGS];
 };
 
 ssize_t ich_number_of_regions(enum ich_chipset cs, const struct ich_desc_content *content);