RAS: Add a menuconfig option with descriptive text

Text taken a previous patch from "Gong Chen" <gong.chen@linux.intel.com>.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1439396985-12812-11-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

drivers/ras/Kconfig

@@ -1,2 +1,32 @@
-config RAS
-	bool
+menuconfig RAS
+	bool "Reliability, Availability and Serviceability (RAS) features"
+	help
+	  Reliability, availability and serviceability (RAS) is a computer
+	  hardware engineering term. Computers designed with higher levels
+	  of RAS have a multitude of features that protect data integrity
+	  and help them stay available for long periods of time without
+	  failure.
+
+	  Reliability can be defined as the probability that the system will
+	  produce correct outputs up to some given time. Reliability is
+	  enhanced by features that help to avoid, detect and repair hardware
+	  faults.
+
+	  Availability is the probability a system is operational at a given
+	  time, i.e. the amount of time a device is actually operating as the
+	  percentage of total time it should be operating.
+
+	  Serviceability or maintainability is the simplicity and speed with
+	  which a system can be repaired or maintained; if the time to repair
+	  a failed system increases, then availability will decrease.
+
+	  Note that Reliability and Availability are distinct concepts:
+	  Reliability is a measure of the ability of a system to function
+	  correctly, including avoiding data corruption, whereas Availability
+	  measures how often it is available for use, even though it may not
+	  be functioning correctly. For example, a server may run forever and
+	  so have ideal availability, but may be unreliable, with frequent
+	  data corruption.
+
+if RAS
+endif