p54: prevent upload of wrong firmwares

This patch will prevent anyone to upload a firmware which was not designed for his device.

There's still a catch:
There is no easy way to detect if a firmware is for PCI or for USB (1st Gen),
because they all share the same LM86 identifier.

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>