USB: ohci-jz4740: Fix spelling in MODULE_ALIAS

platfrom -> platform

Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>