net/bnxt: remove some unused variables

net/bnxt: remove some unused variables

Reported by clang 13.

Bugzilla ID: 881
Fixes: b87abb2e55cb ("net/bnxt: support marking packet")
Fixes: 88badb3aef94 ("net/bnxt: add helper functions for blob/regfile ops")
Cc: stable@dpdk.org
Reported-by: Liang Longfeng <longfengx.liang@intel.com>
Signed-off-by: Conor Walsh <conor.walsh@intel.com>
Acked-by: Somnath Kotur <somnath.kotur@broadcom.com>
Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>