usb: phy: snps: Ensure SIDDQ is disabled for proper functioning

Some platforms may have the SIDDQ enabled by default as a part of
PHY POR. This leads to PHY analog blocks staying down and hence
the PHY is not in a proper state to function.
Ensure that SIDDQ is disabled as a part of init routine.

Change-Id: I6685c34fc69168472d4a97d14e714b9b5a3558b5
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>