metronomefb: don't free firmware twice in error path

Right now, if request_irq or anthing after it fails than we free the firmware
for the second time what might end bad :)

Signed-off-by: Sebastian Siewior <sebastian@breakpoint.cc>
Acked-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>