bnxt_en: Refactor hardware resource data structures.

In preparation for new firmware APIs to allocate hardware resources,
add a new struct bnxt_hw_resc to hold various min, max and reserved
resources.  This new structure is common for PFs and VFs.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>