fix(cpus): fix the rev-var of Cortex-X2

Update the revision and variant information in the
errata ABI file, cortex_X2.S file for erratum ID - 2058056
to match the revision and variant in the latest SDEN.

SDEN documentation:
https://developer.arm.com/documentation/SDEN-1775100/latest

Change-Id: I28ee39949d977c53d6f5243100f0c29bc3c0428c
Signed-off-by: Sona Mathew <sonarebecca.mathew@arm.com>
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 2cf7992..e67fca2 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -685,7 +685,7 @@
    it is still open.
 
 -  ``ERRATA_X2_2058056``: This applies errata 2058056 workaround to Cortex-X2
-   CPU. This needs to be enabled for revisions r0p0, r1p0, and r2p0 of the CPU,
+   CPU. This needs to be enabled for revisions r0p0, r1p0, r2p0 and r2p1 of the CPU,
    it is still open.
 
 -  ``ERRATA_X2_2083908``: This applies errata 2083908 workaround to Cortex-X2