CVE-2026-98893: firmware: arm_scmi: Validate SENSOR_UPDATE payload size

In the Linux kernel, the following vulnerability has been resolved:

firmware: armscmi: Validate SENSORUPDATE payload size

SENSORUPDATE carries one or more sensor readings after the fixed notification header. The parser derives the expected reading count from the sensor description, but it did not verify that the received payload contains those entries before parsing them.

Reject truncated update notifications before reading the variable array.