Revert "OMAPDSS: APPLY: add fifo-merge support"

Revert "OMAPDSS: APPLY: add fifo-merge support"

This reverts commit 690b01b0214c64f1315305fa5b52d012d632c7af.

Adding fifo merge feature as an omapdss internal configuration was a
mistake. We cannot hide from the users of omapdss the complexities of
fifo merge.

This commit removes the fifo merge support, which luckily is easily done
as it was handled totally inside apply.c. Note that this is not a 1:1
revert, but some resolving was needed for the dss_ovl_setup_fifo.

The plan is to try fifo merge again later when it is more clear how the
hardware acts in various situations, and how the omapdrm wants to use
fifo merge.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>