doc: Update the name of profiling based on sysfs

The ./kernel/ksysfs.c defines 'profiling' w/o 'profile' like
"KERNEL_ATTR_RW(profiling)".  We need to synchronize the content between ksys.c
source and kernel doc.

Signed-off-by: Hyeonjun Lim <hjoon0510@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>