Documentation/admin-guide: Add bus lock ratelimit

mainline inclusion
from mainline-v5.12-rc4
commit 9d839c28
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5G10C
CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
commit/?id=9d839c28

Intel-SIG: commit 9d839c Documentation/admin-guide: Add bus lock ratelimit

--------------------------------

Since bus lock rate limit changes the split_lock_detect parameter,
update the documentation for the change.
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NTony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20210419214958.4035512-4-fenghua.yu@intel.com

(cherry picked from commit 9d839c28)
Signed-off-by: NEthan Zhao <haifeng.zhao@linux.intel.com>
Signed-off-by: NJason Zeng <jason.zeng@intel.com>

Documentation/admin-guide/kernel-parameters.txt

@@ -5301,6 +5301,14 @@
 				  exception. Default behavior is by #AC if
 				  both features are enabled in hardware.
 
+			ratelimit:N -
+				  Set system wide rate limit to N bus locks
+				  per second for bus lock detection.
+				  0 < N <= 1000.
+
+				  N/A for split lock detection.
+
+
 			If an #AC exception is hit in the kernel or in
 			firmware (i.e. not while executing in user mode)
 			the kernel will oops in either "warn" or "fatal"