powerpc: Fix output from show_regs

For some reason we've had an explicit KERN_INFO for GPR dumps.  With
recent changes we get output like:

<6>GPR00: 00000000 ef855eb0 ef858000 00000001 000000d0 f1000000 ffbc8000 ffffffff

The KERN_INFO is causing the <6>.  Don't see any reason to keep it
around.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>