dmaengine: altera-msgdma: Fixed some inconsistent function name descriptions

Inconsistent function names describing msgdma_chan_remove() and
msgdma_dma_remove are modified to msgdma_dev_remove() and msgdma_remove().

Remove some warnings found by running scripts/kernel-doc, which is caused
by using 'make W=1'.

drivers/dma/altera-msgdma.c:927: warning: expecting prototype for msgdma_dma_remove(). Prototype was for msgdma_remove() instead.
drivers/dma/altera-msgdma.c:758: warning: expecting prototype for msgdma_chan_remove(). Prototype was for msgdma_dev_remove() instead.

Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Link: https://lore.kernel.org/r/20220706082605.114907-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>