msm: ipa: add support for msm bus scaling

IPA driver adds bus bandwidth request for krypton.
IPA driver needs to support two operating modes, one for nominal mode
operation, another for SVS mode.
Currently it always request bandwidth for nominal mode.

Change-Id: Ib0737393e76dbefd26b647c116e2c82a1817e39c
Signed-off-by: Ravit Katzav <rkatzav@codeaurora.org>