msm: platsmp: Remove extraneous boot_secondary delay

Change msleep_interruptible to usleep. msleep_interruptible
takes around 16 ms to return while the secondary CPU can
come up in about 1.5 ms. usleep is much finer grained and
returns every .5 ms. This allows boot_secondary to complete
much more quickly.

Signed-off-by: Maya Spivak <mspivak@codeaurora.org>
(cherry picked from commit 5e17706)

Change-Id: I49b32101667b1c2bfd7ecacf6a1c96db2a696afc
Signed-off-by: Swetha Basineni <sbasin@codeaurora.org>
Signed-off-by: nobodyAtall <tsogkas@ceid.upatras.gr>
Signed-off-by: garwedgess <garethwilliams21@gmail.com>