common/cnxk: reset stale values on error debug registers

common/cnxk: reset stale values on error debug registers

LF's error debug registers like NIX_LF_SQ_OP_ERR_DBG,
NIX_LF_MNQ_ERR_DBG, NIX_LF_SEND_ERR_DBG captures debug
info for an error detected during LMT operation or meta
enqueue or after meta enqueue granted respectively. HW
sets a valid bit when info is captured and SW is expected
to clear this valid bit by writing 1, else these registers
will show stale values of first interrupt when occurred and
will never update with subsequent interrupts.

Fixes: f6d567b03d28 ("common/cnxk: support NIX IRQ")
Cc: stable@dpdk.org
Signed-off-by: Harman Kalra <hkalra@marvell.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>