MAINTAINERS: adjust file entry in MEDIATEK DMA DRIVER

MAINTAINERS: adjust file entry in MEDIATEK DMA DRIVER

Commit fa3400504824 ("dt-bindings: dma: convert MediaTek High-Speed
controller to the json-schema")  converts mtk-hsdma.txt to
mediatek,mt7622-hsdma.yaml, but misses to adjust its reference in
MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Repair this file reference in MEDIATEK DMA DRIVER.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20240222135847.5160-1-lukas.bulwahn@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>