target/ppc: switch fpr/vsrl registers so all VSX registers are in host endian order

target/ppc: switch fpr/vsrl registers so all VSX registers are in host endian order

When VSX support was initially added, the fpr registers were added at
offset 0 of the VSR register and the vsrl registers were added at offset
1. This is in contrast to the VMX registers (the last 32 VSX registers) which
are stored in host-endian order.

Switch the fpr/vsrl registers so that the lower 32 VSX registers are now also
stored in host endian order to match the VMX registers. This ensures that TCG
vector operations involving mixed VMX and VSX registers will function
correctly.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190307180520.13868-7-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>