msm: cpufreq: Relax constraints on "msm-cpufreq" workqueue

This workqueue is not used in memory reclaim paths, so the
WQ_MEM_RECLAIM flag is not needed. Additionally, there is no
need to restrict the queue to having one in-flight work item.
Remove these constraints.

Change-Id: I9edde40917d3ec885ce061133de20680634321d0
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>