be2net: simplify UFI compatibility checking

The code in be_check_ufi_compatibility() checks to see if a UFI file meant
for a lower rev of a chip is being flashed on a higher rev, which is
disallowed. This patch re-writes the code needed for this check in a much
simpler manner.

Signed-off-by: Vasundhara Volam <vasundhara.volam@avagotech.com>
Signed-off-by: Sathya Perla <sathya.perla@avagotech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>