Bluetooth Central: Discovery of 128bit primary service fails with later versions of gcc.

[lanvis]

Describe the bug
Discovery of 128bit primary service fails with later versions of gcc.
In gatt_find_type(), looks like macro BT_UUID_16 returns wrong value with later gcc versions.

Using gcc ARM version 7.3.1 (BT_UUID_16(uuid)->val) returns 0x2800 (which is correct)

Using gcc ARM version 9.2.1 (BT_UUID_16(uuid)->val) returns 0x2000 (which is incorrect) and leads to a failed discovery.

To Reproduce
Attempt a discovery of a 128bit primary service when configured as a central.

A Ellisys trace is attached showing the Find by value request going out as RFCOMM???
DiscoveryFailGCCNew012020.zip

Environment (please complete the following information):

• OS: Linux 18.04LTS
• Toolchain (Zephyr 2.0.0, ARM gcc 9.2.1)

DiscoveryFailGCCNew012020.zip

[lanvis]

In gatt_find_type(), BT_UUID_16(uuid)->val) returns wrong value in later gcc versions.

[aescolar]

CC @jhedberg @Vudentz

[joerchan]

Since it is Zephyr 2.0.0. This might be already fixed by:
#21186

@lanvis Please check

[lanvis]

Yep ... that is the same bug. Sorry about that. I tested by merging your updates into 2.0 gatt.c file as changes to the file are many.

Many thanks!