V4L/DVB: IR/imon: remove bad ir_input_dev use

The ir_input_dev gets filled in by __ir_input_register, the one
allocated in imon_init_idev was being overwritten by the correct one
shortly after it was initialized (ultimately resulting in a memory
leak). Additionally, there was an ill-advised memcpy into that
extraneous ir_input_dev which gets fixed by this.

Ill-advised memcpy pointed out by Dmitry Torokhov, bad usage of
ir_input_dev pointed out by Maxim Levitsky.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>