gfxstream-protocols: don't strongly type variable

Fixes the following error on some systems

def __init__(self, name: str, retType: VulkanType, parameters: list[VulkanType], origName=None):
   TypeError: 'type' object is not subscriptable

BUG=262595016
TEST=compile and run

Change-Id: Ifdc35d49a9d1427d925d4fb33eba84c0cbbcc50e
1 file changed