arm64: ftrace: remove redundant label

Since commit:

  c4a0ebf8 ("arm64/ftrace: Make function graph use ftrace directly")

The 'ftrace_common_return' label has been unused.

Remove it.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Will Deacon <will@kernel.org>
Tested-by: "Ivan T. Ivanov" <iivanov@suse.de>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220614080944.1349146-4-mark.rutland@arm.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>