Update the kerneldoc function headers to fix build warnings:

drivers/dma/qcom/qcom_adm.c:180: warning: Function parameter or member 'chan' not described in 'adm_free_chan'
drivers/dma/qcom/qcom_adm.c:190: warning: Function parameter or member 'burst' not described in 'adm_get_blksize'
drivers/dma/qcom/qcom_adm.c:466: warning: Function parameter or member 'chan' not described in 'adm_terminate_all'
drivers/dma/qcom/qcom_adm.c:466: warning: Excess function parameter 'achan' description in 'adm_terminate_all'
drivers/dma/qcom/qcom_adm.c:503: warning: Function parameter or member 'achan' not described in 'adm_start_dma'
Signed-off-by: Jonathan McDowell <noodles@earth.li>
Link: https://lore.kernel.org/r/20201126184602.GA1008@earth.liSigned-off-by: Vinod Koul <vkoul@kernel.org>