[][fix issue that free memory which didn't allocate ]

[Description]
Fix issue that free memory which didn't allocate
 - scratch_head didn't allocat memory to it when mtk_dma_init fail

[Release-log]

Change-Id: I3d97be507bd2a1a4e6a4b62ca0ee09d35573b81e
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5028264
1 file changed