octeontx2-pf: Fix graceful exit during PFC configuration failure

During PFC configuration failure the code was not handling a graceful
exit. This patch fixes the same and add proper code for a graceful exit.

Fixes: 99c969a8 ("octeontx2-pf: Add egress PFC support")
Signed-off-by: Suman Ghosh <sumang@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>