dmaengine: sun4i-dma: Demote obvious misuse of kerneldoc to standard comment blocks

No attempt has been made to document any of the demoted functions here.

Fixes the following W=1 kernel build warning(s):

 drivers/dma/sun4i-dma.c:321: warning: Function parameter or member 'priv' not described in '__execute_vchan_pending'
 drivers/dma/sun4i-dma.c:321: warning: Function parameter or member 'vchan' not described in '__execute_vchan_pending'
 drivers/dma/sun4i-dma.c:435: warning: Function parameter or member 'chan' not described in 'generate_ndma_promise'
 drivers/dma/sun4i-dma.c:435: warning: Function parameter or member 'src' not described in 'generate_ndma_promise'
 drivers/dma/sun4i-dma.c:435: warning: Function parameter or member 'dest' not described in 'generate_ndma_promise'
 drivers/dma/sun4i-dma.c:435: warning: Function parameter or member 'len' not described in 'generate_ndma_promise'
 drivers/dma/sun4i-dma.c:435: warning: Function parameter or member 'sconfig' not described in 'generate_ndma_promise'
 drivers/dma/sun4i-dma.c:435: warning: Function parameter or member 'direction' not described in 'generate_ndma_promise'
 drivers/dma/sun4i-dma.c:501: warning: Function parameter or member 'chan' not described in 'generate_ddma_promise'
 drivers/dma/sun4i-dma.c:501: warning: Function parameter or member 'src' not described in 'generate_ddma_promise'
 drivers/dma/sun4i-dma.c:501: warning: Function parameter or member 'dest' not described in 'generate_ddma_promise'
 drivers/dma/sun4i-dma.c:501: warning: Function parameter or member 'len' not described in 'generate_ddma_promise'
 drivers/dma/sun4i-dma.c:501: warning: Function parameter or member 'sconfig' not described in 'generate_ddma_promise'
 drivers/dma/sun4i-dma.c:577: warning: Function parameter or member 'contract' not described in 'get_next_cyclic_promise'
 drivers/dma/sun4i-dma.c:596: warning: Function parameter or member 'vd' not described in 'sun4i_dma_free_contract'

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: "Emilio López" <emilio@elopez.com.ar>
Link: https://lore.kernel.org/r/20200714111546.1755231-10-lee.jones@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>