[media] drivers/media/radio/radio-wl1273.c: use devm_ functions

[media] drivers/media/radio/radio-wl1273.c: use devm_ functions

The various devm_ functions allocate memory that is released when a driver
detaches.  This patch uses these functions for data that is allocated in
the probe function of a platform device and is only freed in the remove
function.

In two cases, the original memory allocation function was kmalloc, which
has been changed to a zeroing allocation to benefit from the devm function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>