ipmi_si_intf tries to access default ports, if no device could be found
elsewhere.  On PPC we have a function to check, if these legacy IO ports
are accessible.  This patch adds a check for these ports on PPC.  This
patch fixes a breakage of IPMI module on PPC machines without a BMC.

Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Acked-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Corey Minyard <minyard@acm.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>