msm: mdss: debug: remove 8994 debug bus support to reduce code size

msm8994 is no longer supported on the current code base. Remove msm8994
debug bus entry table to reduce the code size.

Change-Id: Ib6dea2b9add2c083fba213e96afcec88fe741455
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>