arm64: scripts/sorttable: Implement sorting mcount_loc at boot for arm64

The mcount_loc section holds the addresses of the functions that get
patched by ftrace when enabling function callbacks. It can contain tens of
thousands of entries. These addresses must be sorted. If they are not
sorted at compile time, they are sorted at boot. Sorting at boot does take
some time and does have a small impact on boot performance.

x86 and arm32 have the addresses in the mcount_loc section of the ELF
file. But for arm64, the section just contains zeros. The .rela.dyn
Elf_Rela section holds the addresses and they get patched at boot during
the relocation phase.

In order to sort these addresses, the Elf_Rela needs to be updated instead
of the location in the binary that holds the mcount_loc section. Have the
sorttable code, allocate an array to hold the functions, load the
addresses from the Elf_Rela entries, sort them, then put them back in
order into the Elf_rela entries so that they will be sorted at boot up
without having to sort them during boot up.

Cc: bpf <bpf@vger.kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Cc: Martin  Kelly <martin.kelly@crowdstrike.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/20250218200022.373319428@goodmis.org
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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