Make PAC demangling more generic

At the moment, address demangling is only used by the backtrace
functionality. However, at some point, other parts of the TF-A
codebase may want to use it.
The 'demangle_address' function is replaced with a single XPACI
instruction which is also added in 'do_crash_reporting()'.

Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
Change-Id: I4424dcd54d5bf0a5f9b2a0a84c4e565eec7329ec
diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index 2f44fe8..fa83b4f 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -189,7 +189,7 @@
    that is only required for the assertion and does not fit in the assertion
    itself.
 
--  ``ENABLE_BACKTRACE``: This option controls whether to enables backtrace
+-  ``ENABLE_BACKTRACE``: This option controls whether to enable backtrace
    dumps or not. It is supported in both AArch64 and AArch32. However, in
    AArch32 the format of the frame records are not defined in the AAPCS and they
    are defined by the implementation. This implementation of backtrace only