drm/msm/sde: remove extra entries from interrupt table

Four extra reserved entries are allocated in 88-91. These
entries do not affect lookup logics but are conflicting
with index listed in the documentation. Remove these
extra reserved entries to match index with documentation.

Change-Id: Id9e3a35e9bee9d13b479d7ef65dca1912ea1ff80
Signed-off-by: Alan Kwong <akwong@codeaurora.org>