drm/tilcdc: Add revision handling for FB_CEILING

The commit d8ff0c63fbcb ("drm/tilcdc: Adjust the FB_CEILING address")
added an adjustment of the FB_CEILING address. This is done by decrementing
the address by one.

On the AM335x (rev 0x4F201000) the framebuffer is rotated left over the
display border, because the ceiling address is 8f276fff instead of
8f277000. Since this adjustment isn't necessary for the LCDC v2, the
origin ceiling address should be used.

Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
Signed-off-by: Jyri Sarha <jsarha@ti.com>