Regular Python enumerations create only one instance for members with
the same value, such as:
class MyEnum(Enum):
    foo = 1
    bar = 1

MyEnum.foo and MyEnum.bar are aliases that return the same instance.

DTS needs to return different instances in the above scenario so that we
can map capabilities with different names to the same function that
retrieves the capabilities.

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>