USB: s3c-hsotg: Ensure TX FIFO addresses setup when initialising FIFOs

Some versions of the S3C HS OtG block startup with overlapping TX FIFO
information, so change the fifo_init code to ensure that known values
are set into the FIFO registers at initialisation/reset time.

This also ensures that the FIFO RAM pointers are in a known state
before use.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>