[media] rx51: broken build

As reported by kernel build test:

   In file included from arch/arm/mach-omap2/pdata-quirks.c:15:0:
>> arch/arm/mach-omap2/pdata-quirks.c:536:49: error: 'rx51_lirc_data' undeclared here (not in a function)
     OF_DEV_AUXDATA("nokia,n900-ir", 0, "n900-ir", &rx51_lirc_data),
                                                    ^
   include/linux/of_platform.h:52:21: note: in definition of macro 'OF_DEV_AUXDATA'
       .platform_data = _pdata }
                        ^~~~~~

Since "a92def1b [media] ir-rx51: port to rc-core" the build fails on
some arm configurations.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>