Do not update the next frame buffer close to vertical blank. This is
to avoid situation when the frame changes between writing of
LCDC_DMA_FB_BASE_ADDR_0_REG and LCDC_DMA_FB_CEILING_ADDR_0_REG.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
[Added description to the patch]
Signed-off-by: NJyri Sarha <jsarha@ti.com>