firmware_loader: remove unneeded 'comma' macro

Commit 553671b7 ("firmware_loader: Fix labels with comma for builtin
firmware") added this line, which was unneeded.

The macro 'comma' is defined in scripts/Kbuild.include.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210528173404.169764-1-masahiroy@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>