doc/vm/page_owner.rst: remove content related to -c option

-c option has been removed from page_owner_sort.c.

Remove the usage of -c option from Documentation.

This work is coauthored by
        Shenghong Han
        Yixuan Cao
        Chongxi Zhao
        Jiajian Ye
        Yuhong Feng
        Yongqiang Liu

Link: https://lkml.kernel.org/r/20220326085920.1470081-2-zhangyinan2019@email.szu.edu.cn
Signed-off-by: Yinan Zhang <zhangyinan2019@email.szu.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sean Anderson <seanga2@gmail.com>
Cc: Tang Bin <tangbin@cmss.chinamobile.com>
Cc: Zhenliang Wei <weizhenliang@huawei.com>
Cc: Georgi Djakov <georgi.djakov@linaro.org>
Cc: Chongxi Zhao <zhaochongxi2019@email.szu.edu.cn>
Cc: Jiajian Ye <yejiajian2018@email.szu.edu.cn>
Cc: Yixuan Cao <caoyixuan2019@email.szu.edu.cn>
Cc: Yuhong Feng <yuhongf@szu.edu.cn>
Cc: Yongqiang Liu <liuyongqiang13@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: Message00

Documentation/vm/page_owner.rst

@@ -125,7 +125,6 @@ Usage
    additional function:
 
 	Cull:
-		-c		Cull by comparing stacktrace instead of total block.
 		--cull <rules>
 				Specify culling rules.Culling syntax is key[,key[,...]].Choose a
 				multi-letter key from the **STANDARD FORMAT SPECIFIERS** section.