usb: ehci-sh: fix illegal phy_init() running when platform_data is NULL

If the platform_data is not set, pdata will be uninitialized value.
Since the driver has the following code, if the condition is true when
the pdata is uninitialized value, the driver may jump to the illegal
phy_init().

	if (pdata && pdata->phy_init)
		pdata->phy_init();

This patch also fixes the following warning:

  CC      drivers/usb/host/ehci-hcd.o
drivers/usb/host/ehci-sh.c: In function ‘ehci_hcd_sh_probe’:
drivers/usb/host/ehci-sh.c:104: warning: ‘pdata’ may be used uninitialized in this function

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>