if_smsc: fix reset check

In smsc_phy_init function, when the driver was trying to reset PHY, it
didn't poll for the correct bit (BMCR_RESET) to be cleared. Instead, it
anded it with MII_BMCR (which is 0), so it just exited the loop.

This issue was fixed in Linux in commit d94609200069.

Submitted by: Arshan Khanifar
MFC after: 1 week
Sponsored by: The FreeBSD Foundation