diag: Enhance IPC logging for diag CNTL channel

The patch enables to track the control channel buffer
status, reception of feature mask and error case of
not queueing a read on socket by use of debug logs.

Change-Id: Ibd9bd9a09f6519e31874f8794df3df875e931d25
Signed-off-by: Manoj Prabhu B <bmanoj@codeaurora.org>