security/intel/stm: Remove __attribute__(())

Change-Id: Id35a0a589128ea2dfb2f0e5873d4fa087b0886a9
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77717
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

src/security/intel/stm/StmPlatformSmm.c

@@ -70,7 +70,7 @@ int load_stm_image(uintptr_t mseg)
 struct descriptor {
 	uint16_t limit;
 	uintptr_t base;
-} __attribute__((packed));
+} __packed;
 
 static void read_gdtr(struct descriptor *gdtr)
 {