util/smmstoretool: Alias EfiImageSecurityDatabaseGuid to "secureboot"

Finalise the new support for adding secure boot variables by adding this
alias. db and dbx have this GUID, all others (PKDefault, KEKDefault,
dbDefault, dbxDefault, PK, and KEK) have the "global" GUID.

Change-Id: I58a825498d57c0bc04516fe41fe94924bdff2181
Signed-off-by: Benjamin Doron <benjamin.doron@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88426
Reviewed-by: Sean Rhodes <sean@starlabs.systems>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

util/smmstoretool/guids.c

@@ -32,6 +32,13 @@ const struct guid_alias_t known_guids[] = {
 			{ 0xaa, 0x0d, 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c }
 		},
 	},
+	{
+		"secureboot",
+		{
+			0xd719b2cb, 0x3d3a, 0x4596,
+			{ 0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f }
+		},
+	},
 	{
 		"microsoft",
 		{