msm: mdss: Check histogram interrupt request for REQ type

The histogram interrupt request function requires a type associated
with the request. The type depends on suspend, resume, and new requests
in general. Previously, the new requests type was assumed if it was not
SUSPEND or RESUME. However, now REQ type is no longer assumed as the last
option.

Change-Id: I25f6bd7f58ae24301df2552fa8330df8543db277
Signed-off-by: Benet Clark <benetc@codeaurora.org>