net/bnxt: support two-level priority for TCAMs

Allow TCAM indexes to be allocated from top or bottom.
If the priority is set to 0, allocate from the
lowest tcam indexes i.e. from top. Any other value,
allocate it from the highest tcam indexes i.e. from
bottom.

Signed-off-by: Shahaji Bhosle <sbhosle@broadcom.com>
Signed-off-by: Venkat Duvvuru <venkatkumar.duvvuru@broadcom.com>
Reviewed-by: Randy Schacher <stuart.schacher@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>