platform/x86: panasonic-laptop: remove unused code

The struct pcc_keyinput is not used in panasonic-laptop and in
anywhere in kernel, and it can be removed.

Signed-off-by: Alex Hung <alex.hung@canonical.com>
Acked-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>