Improve the error checking in the IR init and deinit functions.
Based on Darren Salt's dvb-ir patchset.
Signed-off-by: David Hardeman <david@hardeman.nu> Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>