[media] ir-core: make struct rc_dev the primary interface

This patch merges the ir_input_dev and ir_dev_props structs into a single
struct called rc_dev. The drivers and various functions in rc-core used
by the drivers are also changed to use rc_dev as the primary interface
when dealing with rc-core.

This means that the input_dev is abstracted away from the drivers which
is necessary if we ever want to support multiple input devs per rc device.

The new API is similar to what the input subsystem uses, i.e:
rc_device_alloc()
rc_device_free()
rc_device_register()
rc_device_unregister()

[mchehab@redhat.com: Fix compilation on mceusb and cx231xx, due to merge conflicts]
Signed-off-by: David Härdeman <david@hardeman.nu>
Acked-by: Jarod Wilson <jarod@redhat.com>
Tested-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>