octeontx2-af: Fix static code analyzer reported issues

This patch fixes the static code analyzer reported issues
in rvu_npc.c. The reported errors are different sizes of
operands in bitops and returning uninitialized values.

Fixes: 651cd265 ("octeontx2-af: MCAM entry installation support")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>