arm64: fpsimd: Enable FP(floating-point) settings for msm8996

Enable FP and SIMD settings for the MSM8996 during the execution
of the AArch32 processes and disable these settings when you switch
to the AArch64 processes.

This commit also adds CONFIG_ENABLE_FP_SIMD_SETTINGS to support
FP and SIMD settings.

CRs-Fixed: 952837
Change-Id: If9537ca7390d8f08a6b48fb8865d1b349a93bcee
Signed-off-by: Se Wang (Patrick) Oh <sewango@codeaurora.org>
[ztu@codeaurora.org: Resolved conflicts]
Signed-off-by: Zhiqiang Tu <ztu@codeaurora.org>