This change add usb system clock support to OTG Driver. System clock is a 60MHZ input clock to the USB ChipIdea core. This clock is required starting from MDM9615. This change also removes the enforcement for using a phy_reset_clk for reseting the PHY. Starting from MDM9615, PHY reset is not implemented. The core is reset together with the PHY using "usb_hs_clk" signal. Change-Id: Ifa4155269dd46a97a7e57dd28050663a12f54c70 Signed-off-by: Amit Blay <ablay@codeaurora.org>