toshiba_acpi: Change touchpad store to check for invalid values

The function toshiba_touchpad_store is not checking
for invalid values and simply returns silently.

This patch checks for invalid values and returns accordingly.

Signed-off-by: Azael Avalos <coproscefalo@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>

diff --cc drivers/platform/x86/toshiba_acpi.c
Simple merge