cirrus/mac89x0: Remove superfluous interrupt disable/restore

As of commit e4dc601b ("m68k: Disable/restore interrupts in
hwreg_present()/hwreg_write()"), this is no longer needed.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>