[IA64] Remove printk noise on unimplemented SAL_PHYSICAL_ID_INFO

Commit 113134fc

 changed the flow of
control when calling PAL_LOGICAL_TO_PHYSICAL and SAL_PHYSICAL_ID_INFO.
With the change, if a platform did not implement the latter, a useless
printk would appear in the boot log:

	ia64_sal_pltid failed with -1

So let's check the return code and only printk on a true error, and do
not print anything in the unimplemented case. While we're in there,
clean up some stylistic issues too.

Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>