regulator: use consumer->supply_name in debugfs/regulator_summary

Make it easier to identify regulator consumers when consumer device
uses more than one supply.

Before:

regulator ena use open bypass voltage current min max
-----------------------------------------------------------------------------------
regulator-dummy 1 0 2 0 0mV 0mA 0mV 0mV
1-0010 0mV 0mV
1-0010 0mV 0mV

After:

regulator ena use open bypass voltage current min max
-----------------------------------------------------------------------------------
regulator-dummy 1 0 2 0 0mV 0mA 0mV 0mV
1-0010-vccio 0mV 0mV
1-0010-vcc33 0mV 0mV

Signed-off-by: Michał Mirosław <[e-mail]>
Link: https://lore.kernel.org/r/73[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/core.c

···
 		seq_printf(s, "%*s%-*s ",
 			   (level + 1) * 3 + 1, "",
 			   30 - (level + 1) * 3,
+			   consumer->supply_name ? consumer->supply_name :
 			   consumer->dev ? dev_name(consumer->dev) : "deviceless");
 
 		switch (rdev->desc->type) {