soundwire: debugfs: Switch to sdw_read_no_pm

It is rather inefficient to be constantly playing with the runtime
PM reference for each individual register, switch to holding a PM
runtime reference across the whole register output.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20221125142028.1118618-4-ckeepax@opensource.cirrus.com


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