[media] drx-j: propagate returned error from request_firmware()

Fix a smatch warning:
	drivers/media/dvb-frontends/drx39xyj/drxj.c:11711 drx_ctrl_u_code() info: why not propagate 'rc' from request_firmware() instead of (-2)?

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>