net: Factorize MAC address validation from a network interface name
net: Factorize MAC address validation from a network interface name

Two functions were now using the same code to get a MAC address from
a network interface name, and validate it against an expected one.

Signed-off-by: Sebastien Boeuf <90b401417360b1924ef3f520ddee932686110f85@intel.com>

MarioCarrilloA/hyperstart,MarioCarrilloA/hyperstart,MarioCarrilloA/hyperstart