emul: Use DEVICE_DT_GET instead of DT_LABEL

DT nodes aren't guaranteed to define a label property. But emulated bus
controllers currently make use of this property to dispatch to the
associated emulator.

Have emulated bus controllers use DEVICE_DT_GET(node_id) to dispatch to
right target peripheral emulator. This also change makes emul_get_binding
and device_get_binding synonymous in behavior with respect to their
parameters.

This also strictly enforces a 1:1 correspondence between invocations of
DEVICE_DT_DEFINE and EMUL_DEFINE.

Signed-off-by: Aaron Massey <aaronmassey@google.com>
6 files changed