ipmi: Add missing rv in ipmi_parisc_probe()

ipmi: Add missing rv in ipmi_parisc_probe()

Fix

  drivers/char/ipmi/ipmi_si_intf.c: In function 'ipmi_parisc_probe':
  drivers/char/ipmi/ipmi_si_intf.c:2752:2: error: 'rv' undeclared (first use in this function)
  drivers/char/ipmi/ipmi_si_intf.c:2752:2: note: each undeclared identifier is reported only once for each function it appears in

Introduced by commit d02b3709ff8e ("ipmi: Cleanup error return")

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>