powerpc/powernv: Remove duplicate header

Remove linux/printk.h which is included more than once.

Signed-off-by: Sabyasachi Gupta <sabyasachi.linux@gmail.com>
Acked-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>