Reference the chipset capability in LE_Set_Data_Length

The parameters in LE_Set_Data_Length was hard-coded to the maximum
value, which could break some low-end Bluetooth chips.

Tag: #feature
Bug: 178526513
Test: bluetooth_test_gd --gtest_filter="*controller*"
Change-Id: I5299beff2ab0faff12482c038137878d9ced0a7d