board: siemens: iot2050: Fix logical bug in PG1/PG2 detection

This caused the wrong fdtfile to be set and was failing to apply M.2
settings.

Fixes: badaa1f6a7a9 ("boards: siemens: iot2050: Unify PG1 and PG2/M.2 configurations again")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
diff --git a/board/siemens/iot2050/board.c b/board/siemens/iot2050/board.c
index 15f5310..e35e55f 100644
--- a/board/siemens/iot2050/board.c
+++ b/board/siemens/iot2050/board.c
@@ -160,7 +160,7 @@
 	struct iot2050_info *info = IOT2050_INFO_DATA;
 
 	return info->magic == IOT2050_INFO_MAGIC &&
-		strstr((char *)info->name, "-PG2") != NULL;
+		strstr((char *)info->name, "-PG2") == NULL;
 }
 
 static bool board_is_m2(void)