msm: ipa4: IPA PM Unit tests init fix

Destroy the PM before unit testing since every test
case will re-init the PM with their own parameters.
Take out rpmh dependency for unit tests and move in ipa.c.

Change-Id: I4975340b7ba0210aebe0631778fe85c4023feb11
CRs-fixed: 2238471
Signed-off-by: Michael Adisumarta <madisuma@codeaurora.org>