This fixes some issues in the Xilinx support code that are critical to
support the Cortex-R5F cores present in my Xilinx SoCs. The imported
Cortex-R5 xil_cache.c matches the existing information in
bsps/shared/xil/VERSION.
This support code is necessary for many Xilinx-provided bare metal device
drivers supported on ARM, AArch64, and MicroBlaze platforms. Support for
all of these architectures is kept under bsps/include due to multiple
architecture variants being supported which requires complex logic in
the build system. The imported files are and should be able to remain
unmodified. Import information is kept in bsps/shared/xil/VERSION.
