Bluetooth: GAP: Fixed Remote Name restriciton of 32 characters.

The Maximum length of Bluetooth name according to Bluetooth spec is 248
characters.When Remote name is set from 0-32 characters and paired
with DUT, the remote name is displayed correctly in DUT. But, when we
set remote name from 33-248 characters, only the first 32 characters
are displayed and the rest are cropped as the dimension value for
the bluetooth_name_length text field is set as 32. Fixed this
issue by changing the limitation of text field length from 32 to 248 so
that DUT can display upto 248 characters.

CRs-Fixed: 724203

Change-Id: I82a9ec0451e0aed7a07939959b1d0eb3122c636f