msm: ipa_v3: Mitigate usleep_range calls

Calling usleep_range with identical min and max values,
results in a delta of 0us.

This causes the issue that the scheduler gets no chance to re-use an already
scheduled interrupt for this wait which results in a negative performance
impact by adding uninterruptible sleep.

Fix the issue by allowing the delay to take 20% longer than requested.
This should be good enough for these cases.

Signed-off-by: Alex Naidis <alex.naidis@paranoidandroid.co>
Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
Change-Id: I9deb5727dc64370f173e05350383e685482247c4