net/i40e/base: wrap admin queue set/get PHY register funcs

net/i40e/base: wrap admin queue set/get PHY register funcs

These two functions are currently only used in the LED get/set
functions, which are not apart of the VF driver.  So the
i40e_aq_set/get_phy_register functions should be wrapped so they
can be removed from the VF driver.

This was brought up in the Linux community that these functions in
the VF driver had no callers in the tree, so they should be removed.

Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Beilei Xing <beilei.xing@intel.com>