arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature

commit 0a8ea52c upstream.

Add HAVE_REGS_AND_STACK_ACCESS_API feature for arm64, including supporting
functions and defines.

[dave.long@linaro.org: Remove irq stack reference and use of bug.h
inside arch/arm64/include/asm/ptrace.h. ]

Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
[catalin.marinas@arm.com: Remove unused functions]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>