net/bnxt: refactor mapper opcodes

net/bnxt: refactor mapper opcodes

Unify the opcodes of the different enums into a single enum for reuse of
common processors. Also the ADD_PAD opcode is now SET_TO_ZERO.
This change better reflects the intent of the opcode and allows it to be
used in more circumstances without overloading the term pad.
The fields that were setting a constant zero have now been switched to
use the new SET_TO_ZERO opcode as an optimization.  The SET_TO_ZERO does
not copy data into the key/result/mask fields, but rather simply
increments the write pointer.

Signed-off-by: Mike Baucom <michael.baucom@broadcom.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Venkat Duvvuru <venkatkumar.duvvuru@broadcom.com>
Reviewed-by: Kishore Padmanabha <kishore.padmanabha@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>