RISC-V: Support loading Image binary file

Add image-riscv file_type to probe/load Image file type,

As for kexec_load, find the pbase aligned text_offset from image header
and prepare segments for this syscall.

for kexec_file_load, setup the related options and let kernel part to
deal with the Image.

Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Signed-off-by: Simon Horman <horms@kernel.org>
5 files changed