wil6210: refresh FW capabilities during interface up

FW capabilities are currently retrieved only during module
initialization, but userspace can replace the firmware while
interface is down, so refresh the FW capabilities when
interface is up (after FW is loaded) to ensure driver
functionality matches the loaded FW.

Change-Id: I880706bee0700b88e6637efd42de2eef4ea0d8b6
Signed-off-by: Lior David <liord@codeaurora.org>