ehci-msm2: Wait 5ms for phy to enter Low Power Mode if port is enabled

Controller initiates low power mode within 5ms of suspending port.
Hence, wait for 5ms after setting port suspend bit to check if
controller completed low power mode or not. if not, reset link and
phy.

CRs-Fixed: 475695
Change-Id: Icd8b43d5b31df3275bc9b507fe765ccf7a28b417
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>