bnxt_en: Change sp events definitions to represent bit position.

Fix the sp event bits to be bit positions instead of bit values since
the bit helper functions are expecting the former.

Signed-off-by: Jeffrey Huang <huangjw@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>