mfd: omap-usb-host: bug fix for 3.9

[Roger Quadros]

Hi Samuel,

One of my patch that I sent for 3.9 introduces a bug that fails to
update the port mode hostconfig register. Because of that, the port modes will
always be 0 (i.e. EHCI PHY mode) and other modes will not work. PHY mode will
work, so beagle/panda have no issues.

Since my hardware setup uses only PHY mode, I couldn't catch this problem earlier.

Below is the fix.