Fix the malfunction of gatt write request

Fix the malfunction of gatt write request

[Model] All
[BinType] AP
[Customer] OPEN

[Issue#] P200428-04425
[Request] Internal
[Occurrence Version] N/A

[Problem] Some application call bt_gatt_client_write_value() repeately. (Write req)
 If gatt client app call API before callback invoked,
 inprogress error is not returned.
[Cause & Measure] ATT is sequential transaction protocol. So return inprogress error
 before write completed callback invoked.
[Checking Method] n/a

[Team] Convergence BT
[Developer] Injun Yang
[Solution company] Samsung
[Change Type] Specification change

Change-Id: I76eb97e124a739990d3210c3f3c3fa7354b605f1
Signed-off-by: Wootak Jung <wootak.jung@samsung.com>