ABI: sysfs-class-devfreq-event: use the right wildcards on What

On most ABI files, the wildcards are used as <x>, instead of (x).

Replace it to make it using a more standard wildcard. That helps
get_abi.pl to convert it into a regex.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Link: https://lore.kernel.org/r/3a0b6a[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-class-devfreq-event

···
-What:		/sys/class/devfreq-event/event(x)/
+What:		/sys/class/devfreq-event/event<x>/
 Date:		January 2017
 Contact:	Chanwoo Choi <[e-mail]>
 Description:
 		Provide a place in sysfs for the devfreq-event objects.
 		This allows accessing various devfreq-event specific variables.
-		The name of devfreq-event object denoted as 'event(x)' which
+		The name of devfreq-event object denoted as 'event<x>' which
 		includes the unique number of 'x' for each devfreq-event object.
 
-What:		/sys/class/devfreq-event/event(x)/name
+What:		/sys/class/devfreq-event/event<x>/name
 Date:		January 2017
 Contact:	Chanwoo Choi <[e-mail]>
 Description:
-		The /sys/class/devfreq-event/event(x)/name attribute contains
+		The /sys/class/devfreq-event/event<x>/name attribute contains
 		the name of the devfreq-event object. This attribute is
 		read-only.
 
-What:		/sys/class/devfreq-event/event(x)/enable_count
+What:		/sys/class/devfreq-event/event<x>/enable_count
 Date:		January 2017
 Contact:	Chanwoo Choi <[e-mail]>
 Description:
-		The /sys/class/devfreq-event/event(x)/enable_count attribute
+		The /sys/class/devfreq-event/event<x>/enable_count attribute
 		contains the reference count to enable the devfreq-event
 		object. If the device is enabled, the value of attribute is
 		greater than zero.