platform/x86: fujitsu-laptop: Fix radio LED detection

Radio LED detection method implemented in commit 4f62568c
("fujitsu-laptop: Support radio LED") turned out to be incorrect as it
causes a radio LED to be erroneously detected on a Fujitsu Lifebook E751
which has a slide switch (and thus no radio LED).  Use bit 17 of
flags_supported (the value returned by method S000 of ACPI device
FUJ02E3) to determine whether a radio LED is present as it seems to be a
more reliable indicator, based on comparing DSDT tables of four Fujitsu
Lifebook models (E744, E751, S7110, S8420).

Fixes: 4f62568c

 ("fujitsu-laptop: Support radio LED")
Reported-by: Heinrich Siebmanns <harv@gmx.de>
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Tested-by: Heinrich Siebmanns <harv@gmx.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>