Add skiboot 5.3.1 release notes

Signed-off-by: Stewart Smith <[email protected]>

doc/release-notes/skiboot-5.3.1.txt

@@ -0,0 +1,36 @@
+skiboot-5.3.1
+-------------
+
+skiboot-5.3.1 was released on Wednesday August 10th, 2016.
+
+This is the 2nd stable release of skiboot 5.3, the new stable release of
+skiboot (first released with 5.3.0 on August 2nd, 2016).
+
+Skiboot 5.3.1 replaces skiboot-5.3.0 as the current stable version. It contains
+a few minor bug fixes.
+
+This release follows the Skiboot stable rules, see doc/stable-skiboot-rules.txt.
+
+Over skiboot-5.3.0, the following fixes are included:
+
+FSP systems:
+- FSP/ELOG: elog_enable flag should be false by default
+    This issue is one of the corner case, which is related to recent change
+    went upstream and only observed in the petitboot prompt, where we see
+    only one error log instead of getting all error log in
+    /sys/firmware/opal/elog.
+
+NVLink systems (i.e. Garrison):
+- npu: reword "error" to indicate it's actually a warning
+    Without this patch, you get spurious FirmWare Test Suite (FWTS) warnings
+    about NVLink not working on machines that aren't fully populated with
+    GPUs.
+- hmi: Clean up NPU FIR debug messages
+    With the skiboot log set to debug, the FIR (and related registers) were
+    logged all in the same message.  It was too much for one line, didn't
+    clarify if the numbers were in hex, and didn't show leading zeroes.
+
+General:
+- asm: Fix backtrace for unexpected exception
+- correct the log level from PR_ERROR down to PR_INFO for some skiboot
+  log messages.