msm: board-8064: Fix MHL USB high speed switch regulator name

commit 56dc742d (USB: msm_otg: Rename MHL USB high speed switch
regulator name) renamed MHL USB high speed switch regulator name
from mhl_ext_3p3v to mhl_usb_hs_switch in OTG driver.  Update the
same for 8064 board otherwise USB lines are not routed to USB PHY.

Change-Id: I1062cbc1440487881b64334799eaf488700dc102
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>