net: ipa: use usleep_range()

65;6003;1c
The use of msleep() for small periods (less than 20 milliseconds) is
not recommended because the actual delay can be much different than
expected.

We use msleep(1) in several places in the IPA driver to insert short
delays.  Replace them with usleep_range calls, which should reliably
delay a period in the range requested.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>