bnxt_en: Fix the 'Invalid VF' id check in bnxt_vf_ndo_prep routine.

bnxt_en: Fix the 'Invalid VF' id check in bnxt_vf_ndo_prep routine.

In bnxt_vf_ndo_prep (which is called by bnxt_get_vf_config ndo), there is a
check for "Invalid VF id". Currently, the check is done against max_vfs.
However, the user doesn't always create max_vfs. So, the check should be
against the created number of VFs. The number of bnxt_vf_info structures
that are allocated in bnxt_alloc_vf_resources routine is the "number of
requested VFs". So, if an "invalid VF id" falls between the requested
number of VFs and the max_vfs, the driver will be dereferencing an invalid
pointer.

Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Venkat Devvuru <venkatkumar.duvvuru@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>