media: radio-raremono: remove redundant initialization of freq

Variable freq is initialized to f->frequency however this value
is never read and freq is later updated; hence the initialization
is redundant and can be removed.

Cleans up clang warning:
drivers/media/radio/radio-raremono.c:257:6: warning: Value stored
to 'freq' during its initialization is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>