powerpc/hvsi: Fix endianness issues in the HVSI driver

This patch fixes several endianness issues detected when running the HVSI
driver in little endian mode.

These issues are raised in little endian mode because the data exchanged in
memory between the kernel and the hypervisor has to be in big endian
format. This exhibits as errors such as:

  irq: (null) didn't like hwirq-0x1000a00 to VIRQ16 mapping (rc=-22)
  hvsi_console_init: couldn't create irq mapping for 0x1000a00

The data structures already have endian annotations, and sparse is
generating numerous warnings based on those. This commit fixes all of
them.

Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Jiri Slaby <jslaby@suse.cz>
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-kernel@vger.kernel.org
[mpe: Flesh out change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>