[V2] dmaengine: stm32-mdma: fix spelling mistake: "avalaible" -> "available"

From: Vinod Koul <hidden>
Date: 2018-05-02 04:24:27
Also in: kernel-janitors, linux-arm-kernel, lkml

On Sat, Apr 28, 2018 at 11:03:52PM +0100, Colin King wrote:

From: Colin Ian King <redacted>

Trivial fix to spelling mistake in dev_err error message text and make
channel plural.

Applied, thanks