objtool: Append "()" to function name in "unexpected end of section" warning

Append with "()" to clarify it's a function.

Before:

  vmlinux.o: warning: objtool: cdns_mrvl_xspi_setup_clock: unexpected end of section .text.cdns_mrvl_xspi_setup_clock

After:

  vmlinux.o: warning: objtool: cdns_mrvl_xspi_setup_clock(): unexpected end of section .text.cdns_mrvl_xspi_setup_clock

Fixes: c5995abe ("objtool: Improve error handling")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/692e1e0d0b15a71bd35c6b4b87f3c75cd5a57358.1743481539.git.jpoimboe@kernel.org