powerpc: Reduce printk from pseries_mach_cpu_die()

Remove debug printks in pseries_mach_cpu_die().  These are
noisy at runtime.  Traceevents can be added to instrument this
section of code.

The following KERN_INFO printks are removed:

cpu 62 (hwid 62) returned from cede.
Decrementer value = b2802fff Timebase value = 2fa8f95035f4a
cpu 62 (hwid 62) got prodded to go online
cpu 58 (hwid 58) ceding for offline with hint 2

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>