LinuxKPI: add __counted_by_le() and __counted_by_be()

The former is needed by a wireless driver at v6.17.

MFC after:	3 days
Reviewed by:	dumbbell, emaste
Differential Revision: https://reviews.freebsd.org/D53203

sys/compat/linuxkpi/common/include/linux/compiler.h

@@ -31,6 +31,7 @@
 #define	_LINUXKPI_LINUX_COMPILER_H_
 
 #include <sys/cdefs.h>
+#include <sys/endian.h>
 
 #define __user
 #define __kernel
@@ -79,6 +80,13 @@
 #else
 #define	__counted_by(_x)
 #endif
+#if BYTE_ORDER == LITTLE_ENDIAN
+#define	__counted_by_le(_x)		__counted_by(_x)
+#define	__counted_by_be(_x)
+#else
+#define	__counted_by_le(_x)
+#define	__counted_by_be(_x)		__counted_by(_x)
+#endif
 
 #define	likely(x)			__builtin_expect(!!(x), 1)
 #define	unlikely(x)			__builtin_expect(!!(x), 0)