sb/intel/lynxpoint/me: Use C99 flexible arrays

Use C99 flexible arrays instead of older style of one-element or
zero-length arrays.
It allows the compiler to generate errors when the flexible array does
not occur at the end in the structure.

Change-Id: If31cbc5ae184c4eb66011666c1bb655fa16afba0
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76781
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/southbridge/intel/lynxpoint/me.c

@@ -723,7 +723,7 @@ static u32 me_to_host_words_pending(void)
 
 struct mbp_payload {
 	union mbp_header header;
-	u32 data[0];
+	u32 data[];
 };
 
 /*

src/southbridge/intel/lynxpoint/me.h

@@ -462,7 +462,7 @@ struct mbp_icc_profile {
 	u8  icc_profile_index;
 	u8  reserved;
 	u32 icc_reg_bundles;
-	struct icc_address_mask icc_address_mask[0];
+	struct icc_address_mask icc_address_mask[];
 } __packed;
 
 struct tdt_state_flag {