[POWERPC] ppc: use syslog macro for the printk log level

Use the appropriate logging macro for the priority level for that
printk call.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>