Correct the interrupt handler in sh4 serial device, return the correct
value and check for what is anabled in the SCSCR register. The sh7722 is
broken just sending a break using minicom.
Signed-off-by: NMichael Trimarchi <trimarchimichael@yahoo.it>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>