platform/x86: fujitsu-laptop: rename call_fext_func() arguments

Rename call_fext_func() arguments so that each argument's name signifies
its role:

  - cmd -> func: sub-function to call (flags, buttons etc.),
  - arg0 -> op: operation to perform (get, set, get capabilities etc.),
  - arg1 -> feature: feature to act on (e.g. which LED), if relevant,
  - arg2 -> state: state to set (e.g. LED on or off), if relevant.

Adjust whitespace to make checkpatch happy.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>