bnxt_en: Check additional resources in bnxt_check_rings()

bnxt_check_rings() is called to check if we have enough resource
assets to satisfy the new number of ethtool channels.  If the asset
test fails, the ethtool operation will fail gracefully.  Otherwise
we will proceed and commit to use the new number of channels.  If it
fails to allocate any resources, the chip will fail to come up.

For completeness, check all possible resources before committing to
the new settings.  Add the missing ring group and RSS context asset
tests in bnxt_check_rings().

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>