halapi: Add new functions to get information of hal_backend structure

halapi: Add new functions to get information of hal_backend structure

The hal-api-common defines the common hal_backend structure for all hal
backend driver. Add new functions to provide the information of
hal_backend structure because of user request. Add the detailed function
roles as following:

[Newly added functions]
- hal_common_get_backend_abi_version(enum hal_module module);
  : Get the backend HAL ABI version according to the type of HAL module

- hal_common_get_backend_name(enum hal_module module, char *name, int size);
  : Get the backend name according to the type of HAL module

- hal_common_get_backend_vendor(enum hal_module module, char *vendor, int size);
  : Get the backend vendor description according to the type of HAL module

Change-Id: I2060e9047b60c029e161dc18f3981185a0f724a1
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>