media: i2c: s5c73m3: return 0 instead of 'ret'.

Since 'ret' is known to be 0, just return '0'. This fixes a smatch warning:

s5c73m3-core.c:439 __s5c73m3_s_stream() warn: missing error code? 'ret'

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>