remove build warning

remove build warning

Touchscreen_init calls the open function of hal at the beginning of the boot with the call stack below.
So the open function of hal is never called at the same time in multi-thread.

Therefore, we can use safely readdir in deviced.

0  touchscreen_init
1  0x2a00b02c in devices_init (data=0x0) at /usr/src/debug/deviced-2.0.0/src/core/devices.c:102
2  0x2a00e424 in deviced_main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/deviced-2.0.0/src/core/main.c:93
3  0x2a0078f4 in main (argc=1, argv=0xbefffe64) at /usr/src/debug/deviced-2.0.0/src/core/main.c:123

Signed-off-by: INSUN PYO <insun.pyo@samsung.com>
Change-Id: Ieb4ded94379c01592cabd85a5ed6eb525042bc97
(cherry picked from commit 4a8b1ec8da47eb05d58d1b67fcb678cc7755d27e)