firewire: replace tricky statement by two simple ones

firewire: replace tricky statement by two simple ones

struct fw_driver::remove returns void, still the comma expression's value
is zero. This is harder to parse than necessary, so replace the single
expression by two easier ones.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Link: https://lore.kernel.org/r/20210126221444.713837-1-uwe@kleine-koenig.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>