mt76x0: remove unused dma.c source file

Remove unused dma.c source file since dma related routines are no
longer used

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
4 files changed