firmware: arm_scmi: Ensure scmi_devices are always matched by name as well

firmware: arm_scmi: Ensure scmi_devices are always matched by name as well

Currently, devices without a name in the id_table cannot register drivers,
and no scmi_device is created without a name via scmi_device_create().
However, the function __scmi_device_create() allows devices with no name,
which are then labeled as "unknown."

Removes support for matching scmi_device instances without a name,
ensuring consistency across the driver registration and probing process.

Message-Id: <20250317-b4-scmi_minor_cleanup-v2-1-f4be99bd9864@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>