1. correct the armv8-r fpu flag from vfpv3-d16 to fpv5-sp-d16
2. add neon support
This commit updates the build script to specify the FPU type of
`fpv5-sp-d16` when the processor is configured with a single-precision
FPU, and `neon-fp-armv8` when the processor is configured with a
double-precision + Advanced SIMD-capable FPU.
Note that the `fp-armv8` FPU type is an alias for double-precision FPv5
with 32 double-precision registers (refer to the GCC
`gcc/config/arm/arm-cpus.in` for more details); NEON is always
specified in case of a double-precision configuration because the
Cortex-R52 can only be configured as such.
Reference:
https://developer.arm.com/Processors/Cortex-R52
Instruction set:
Arm and Thumb-2. Supports DSP instructions and a configurable Floating-Point
Unit either with single-precision or double precision and Neon.
Signed-off-by: chao an <anchao@lixiang.com>
dedb4c95c9