platform/x86: intel-hid: remove redundant set_bit() call

Remove redundant set_bit() call for KEY_RFKILL as it is already made by
sparse_keymap_setup() due to KEY_RFKILL being assigned to event code 8
in intel_hid_keymap.

Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-and-tested-by: Alex Hung <alex.hung@canonical.com>