Support for AArch32 SIMD/Floating-point registers

Support for AArch32 SIMD/Floating-point registers

This patch adds support for read/write of SIMD and floating-point register in AArch32 mode.
This patch is tested using Raspberry Pi3 halted in AArch32 mode with FP/SIMD enabled.
Software need to make sure floating-point and SIMD unit is enabled.

Change-Id: I2b3b8af02257c6420e5a70c6f4c91f839c1f5ee5
Signed-off-by: Omair Javaid <omair.javaid@linaro.org>
Reviewed-on: http://openocd.zylin.com/4446
Tested-by: jenkins
Reviewed-by: Matthias Welwarsky <matthias@welwarsky.de>