skiboot v7.1 release notes

Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>

doc/release-notes/skiboot-7.1.rst

@@ -3,10 +3,23 @@
 skiboot-7.1
 ===========
 
+skiboot v7.1 was released on Monday Sep 18th 2023. It is the first release of
+the skiboot 7.1 series, which becomes the new stable release following the
+:ref:`skiboot-7.0` release, first released Tuesday Oct 26th 2021.
+
+Changes in this release are mostly bug fixes, refactoring improvements, and
+some code deprecation/obsoletion.
+
 New Features
 ------------
 Removed OPAL calls
 ^^^^^^^^^^^^^^^^^^
 The OPAL_PCI_SET_MVE_ENABLE and OPAL_PCI_SET_MVE calls were removed, as they
 were noops. Support for IODA1 and both calls was removed from the Linux kernel
 in v6.5-rc1.
+
+Optional POWER8 support
+^^^^^^^^^^^^^^^^^^^^^^^
+Most POWER8 code has been conditionalized, making it possible to omit support by
+building with `CONFIG_P8=0`. The result is a smaller binary targeting POWER9 as
+the baseline CPU.