input: add input device information functions

input: add input device information functions

Add input functions to get device information.
Input event on/off option can be handled by device id number.
Input device id numbers can be get by below functions.
Also, input device name can be obtained by device id number.

These are function prototype to be added.
int device_input_get_devices(device_input_type_e input_type, int** input_ids, int* num_input_ids)
-> With device_input_type_e, input device id list can be obtained by this function.
	input_ids will be filled with input device ids.
	num_input_ids will be set with number of input device ids.

int device_input_put_devices(int** input_ids)
-> If input id list(input_ids) is no longer in use, it can be free by this function.

int device_input_get_default_device(device_input_type_e input_type, int *input_dev_id)
-> With device_input_type_e, input default device id number can be get from config file.

int device_input_get_device_name(int input_device_id, char **input_device_name)
-> With input device id number, input device name can be get by this function.

Change-Id: I0afd1340ecc6d7f0a8dd1c4083da169c77b88e3a
Signed-off-by: Yunhee Seo <yuni.seo@samsung.com>