usb: ehci-msm-hsic: fix runtime suspend when IPA not used

Commit aa165c5ce19e06d23b70b2829d555a3a4a09b4cc "ehci: hsic: add
suspend/resume handshake with ipa resource manager" introduced a
bug in which the controller does not enter runtime suspend even
though all its child devices are suspended. This was caused by
an errant call to pm_runtime_get() by the usb_bam driver, which
unless the "consider_ipa_handshake" feature is enabled, has no
other means to decrement the PM counter until the driver's
remove() is called.

As the usb_bam interaction is only used in the case of the new
"consider_ipa_handshake" flag, fix the problem by only calling
msm_bam_set_hsic_host() if the flag is set.

Change-Id: I175ef08118d40d1ccb4b3192fb070701ea80060c
Signed-off-by: Jack Pham <jackp@codeaurora.org>