Documentation/sparse: drop __CHECK_ENDIAN__

It's no longer used.

Signed-off-by: Michael S. Tsirkin <[e-mail]>

Documentation/dev-tools/sparse.rst

···
 have already built it.
 
 The optional make variable CF can be used to pass arguments to sparse.  The
-build system passes -Wbitwise to sparse automatically.  To perform endianness
-checks, you may define __CHECK_ENDIAN__::
-
-        make C=2 CF="-D__CHECK_ENDIAN__"
-
-These checks are disabled by default as they generate a host of warnings.
+build system passes -Wbitwise to sparse automatically.

Documentation/translations/zh_CN/sparse.txt

···
 如果你已经编译了内核，用后一种方式可以很快地检查整个源码树。
 
 make 的可选变量 CHECKFLAGS 可以用来向 sparse 工具传递参数。编译系统会自
-动向 sparse 工具传递 -Wbitwise 参数。你可以定义 __CHECK_ENDIAN__ 来进行
-大小尾检查。
-
-	make C=2 CHECKFLAGS="-D__CHECK_ENDIAN__"
-
-这些检查默认都是被关闭的，因为他们通常会产生大量的警告。
+动向 sparse 工具传递 -Wbitwise 参数。