Settings: Fix error when input WLAN Direct name with long Chinese name

Caused by beyond the limitation from driver layer which the
characters of WLAN Direct name can not exceed 32 bytes.

Add the codes to limit the characters of user input.

CRs-Fixed: 646426

Change-Id: I1ddf6d69940e0685c159e1b6329e0ee5fbbac222
P2P : Fix for P2P group name

When device is in Chinese language, P2P group SSID names will be encoded
into UTF-8 hex format. When displaying group SSID in UI Settings, this
UTF-8 should be converted back to UTF-8 binary format.
Implemented method to convert UTF-8 hex to UTF-8 binary format. When
group is created, it checks the hex format by looking '\x' sequence,
then converts to binary format.

Change-Id: I381b9e6c89ea4c82d41d2d4b69effe0d5e71d2e8
CRs-Fixed: 661989