[media] s5p-mfc: Fix unbalanced call to clock management

[media] s5p-mfc: Fix unbalanced call to clock management

Clock should be turned off after calling s5p_mfc_init_hw() from the
watchdog worker, like it is already done in the s5p_mfc_open() which also
calls this function.

Fixes: af93574678108 ("[media] MFC: Add MFC 5.1 V4L2 driver")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: stable@vger.kernel.org # v3.7+
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>