arm64: mte: Document the core dump file format

Add the program header definition and data layout for the
PT_ARM_MEMTAG_MTE segments.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Luis Machado <luis.machado@linaro.org>
Link: https://lore.kernel.org/r/20220131165456.2160675-6-catalin.marinas@arm.com


Signed-off-by: Will Deacon <will@kernel.org>