drivers: dma: dma_nxp_edma: allow channel re-configuration

Currently, the state transition function doesn't allow
the re-configuration of an already configured channel
(i.e: CHAN_CONFIGURED -> CHAN_CONFIGURED transition). This
causes problems when using `pulseaudio` and `SOF` because
the same channel ends up being configured multiple times
in the beginning due to how pulse seems to work. Logically
speaking, re-configuring an already configured channel is
not wrong so this commit solves the issue by allowing
the CHAN_CONFIGURED -> CHAN_CONFIGURED transition.

Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>