platform/x86: intel_mid_powerbtn: Take a copy of ddata

The driver gets driver_data from memory that is marked as const (which
is probably put to read-only memory) and it then modifies it. This
likely causes some sort of fault to happen.

Fix this by taking a copy of the structure.

Fixes: c94a8ff1 ("platform/x86: intel_mid_powerbtn: make mid_pb_ddata const")
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>