target-arm: fix neon vsri, vshl and vsli ops

target-arm: fix neon vsri, vshl and vsli ops

Shift by immediate value is incorrectly overwritten by a temporary
variable in the processing of NEON vsri, vshl and vsli instructions.
This patch has been revised to also include a fix for the special
case where the code would previously try to shift an integer value
over 31 bits left/right.

Signed-off-by: Juha Riihimäki <juha.riihimaki@nokia.com>
Acked-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>