drm: msm: sde: remove user commit validity check

Such validity check will let Android FDR test failed.
This is because kernel has enabled interrupts, and
access registers, but with this validity check, LK also
co-exists with kernel, while it has disabled interrupts.
Hence conflict happens.

CRs-Fixed: 2247983 2258043
Change-Id: I21be9ae2beeaa0bc187aee241572ce530b9bc93a
Signed-off-by: Guchun Chen <guchunc@codeaurora.org>