[][Fix CDM RFIFO for panther cheetah]

Fix code issue for Panther / Cheetah
 -We have found a possible occurrence of Ethernet Tx hang issue in UES test topology,
which is caused by DMA FIFO overflow event. It's confirmed that enlarging DMA reserve buffer size can tackle the root cause of this problem


Change-Id: I253ec6d5c944b1ccd3e4ca074a68b8932183b5c3
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/5884357
2 files changed