MAINTAINERS: Update ARM SC5xx

MAINTAINERS: Update ARM SC5xx

After years of developing the ADI ADSP platform, Timesys was purchased
by another company and is no longer contracted to maintain the platform.

Utsav is leaving ADI after contributing to ADSP SoCs for the last 3
years. He is a founding member of the in-house team supporting the
chips.

Linux support at ADI has been consolidated. Use the company-wide mailing
list and git repository.

Signed-off-by: Philip Molloy <philip.molloy@analog.com>
Reviewed-by: Greg Malysa <malysagreg@gmail.com>