net/bnxt: support internal encap records

net/bnxt: support internal encap records

Modifications to allow internal encap records to be supported:
- Modified the mapper index table processing to handle encap without an
  action record
- Modified the session open code to reserve some 64 Byte internal encap
  records on tx
- Modified the blob encap swap to support encap without action record

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: Ajit Khaparde <ajit.khaparde@broadcom.com>