video: s3c-fb: Fix typo in definition of VIDCON1_VSTATUS_FRONTPORCH value

The correct value for VIDCON1_VSTATUS_FRONTPORCH is 3, not 0.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>