dmaengine: ti: k3-psil: optimize struct psil_endpoint_config for size

dmaengine: ti: k3-psil: optimize struct psil_endpoint_config for size

Optimize struct psil_endpoint_config for size by
- reordering fields
- grouping bitfields
- change mapped_channel_id type to s16 (32K channel is enough)
- default_flow_id type to s16 as it's assigned to -1

before:
text            data     bss    dec	        hex	filename
12654100	5211472	 666904	18532476	11ac87c	vmlinux

after:
12654100	5208528	 666904	18529532	11abcfc	vmlinux

diff: 2944 bytes

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Link: https://lore.kernel.org/r/20210129193117.28833-1-grygorii.strashko@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>