rtnetlink: clean up SR-IOV config interface
rtnetlink: clean up SR-IOV config interface

This patch consists of a few minor cleanups to the SR-IOV
configurion code in rtnetlink.
- Remove unneccesary lock
- Remove unneccesary casts
- Return correct error code for no driver support

These changes are based on comments from Patrick McHardy

Signed-off-by: Mitch Williams <acfbed6236bdabd688e979c4a715822951672d73@intel.com>
Signed-off-by: Jeff Kirsher <87e35f5be20bb3e67f4ba6b86f5f6be3085b1b3a@intel.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs