ralink: fix hw status almost full not work on mt7620 and mt7621

ralink: fix hw status almost full not work on mt7620 and mt7621

the old FE_INT_STATUS register becomes two registers.
FE_INT_STATUS and INT_STATUS. so the hw status almost full
must change to read from FE_INT_STATUS register.
tx/rx done read from INT_STATUS register.

mt7620 datasheet define CNT_GDM1_AF at BIT(29).
but after test it should be BIT(13). why?

Signed-off-by: michael lee <igvtee@gmail.com>
SVN-Revision: 44371