build(mpam): add new build option CTX_INCLUDE_MPAM_REGS

New build option CTX_INCLUDE_MPAM_REGS is added to select
if the firmware needs to save the MPAM EL2 registers during world
switches. This option is currently disabled as MPAM is only
enabled for NS world.

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: Ie2e5e184cdb65f7e1a98d8fe81590253fd859679
diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index 7ca0300..3d409e3 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -180,6 +180,11 @@
    registers to be included when saving and restoring the CPU context. Default
    is 0.
 
+-  ``CTX_INCLUDE_MPAM_REGS``: Boolean option that, when set to 1, will cause the
+   Memory System Resource Partitioning and Monitoring (MPAM)
+   registers to be included when saving and restoring the CPU context.
+   Default is '0'.
+
 -  ``CTX_INCLUDE_MTE_REGS``: Numeric value to include Memory Tagging Extension
    registers in cpu context. This must be enabled, if the platform wants to use
    this feature in the Secure world and MTE is enabled at ELX. This flag can