target/ppc: receive high/low as argument in get/set_cpu_vsr

target/ppc: receive high/low as argument in get/set_cpu_vsr

Changes get_cpu_vsr to receive a new argument indicating whether the
high or low part of the register is being accessed. This change improves
consistency between the interfaces used to access Vector and VSX
registers and helps to handle endianness in some cases.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Message-Id: <20211104123719.323713-12-matheus.ferst@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>