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

arch/arm64/kernel/entry-ftrace.S

@@ -102,7 +102,6 @@ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL)
  * x19-x29 per the AAPCS, and we created frame records upon entry, so we need
  * to restore x0-x8, x29, and x30.
  */
-ftrace_common_return:
 	/* Restore function arguments */
 	ldp	x0, x1, [sp]
 	ldp	x2, x3, [sp, #S_X2]