CVE-2026-98892: firmware: arm_scmi: Validate BASE_ERROR_EVENT payload size

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

firmware: armscmi: Validate BASEERROREVENT payload size

BASEERROREVENT carries a variable number of message reports, with the count encoded in errorstatus. The notification parser used that count without checking whether the received payload contained all reported entries.

Reject truncated payloads before copying the report array.