target/ppc: remove getVSR()/putVSR() from mem_helper.c

target/ppc: remove getVSR()/putVSR() from mem_helper.c

Since commit 8a14d31b00 "target/ppc: switch fpr/vsrl registers so all VSX
registers are in host endian order" functions getVSR() and putVSR() which used
to convert the VSR registers into host endian order are no longer required.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20190616123751.781-3-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>