MMFMWK-7996 gstimxcommon: add marcos for mscale 845s chip code

upstream status: imx specific
diff --git a/gst-libs/gst/gstimxcommon.h b/gst-libs/gst/gstimxcommon.h
index 4b3658a..fb7b8e1 100755
--- a/gst-libs/gst/gstimxcommon.h
+++ b/gst-libs/gst/gstimxcommon.h
@@ -119,6 +119,7 @@
 #define HAS_DCSS() check_feature(imx_chip_code(), DCSS)
 
 #define IS_HANTRO() ((CC_MX8M == imx_chip_code()) || (CC_MX8MM == imx_chip_code()) )
+#define IS_IMX8MM() (CC_MX8MM == imx_chip_code())
 #define IS_AMPHION() (CC_MX8QXP == imx_chip_code())