USB: fix Unaligned access in EHCI driver

I get following warnings on spar64:
Kernel unaligned access at TPC[1000c9e4] ehci_hub_control+0x54c/0x68c [ehci_hcd]

Despite of the comment in the patched code, the type cast used there
does make unaligned access. The fix was made as it's done in
ohci-hub.c.

Signed-off-by: Max Dmitrichenko <dmitrmax@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>