3rdparty/libgfxinit: Uprev to avoid new GCC 13 warning

This pulls just one commit:
* commit a4be8a21b0e2 (Avoid warning '"Pos32" is already use-visible')

Change-Id: I908d5f2b98e2251a09c587d82b3e7fab55b338a2
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76868
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3rdparty/libgfxinit

@@ -1 +1 @@
-Subproject commit 732feb414dcb58e9282d25fc8c569d372d179f47
+Subproject commit a4be8a21b0e2c752da0042c79aae5942418f53e2