[][kernel][common][eth][fix missing DMA tx/rx monitor]

[Description]
Fix ethernet missing DMA tx/rx monitor for TDMA rx.
The original version only calls 6 monitor functions, but the monitor
function array has 7 ops.

Use ARRAY_SIZE to loop through the function pointer array instead of a
constant.

[Release-log]
N/A

Change-Id: I5afb675aa95bcad79d50d5fd76d7aece27b89a15
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7711016
1 file changed