feat(tcr2): support FEAT_TCR2

Arm v8.9 introduces FEAT_TCR2, adding extended translation control
registers. Support this, context switching TCR2_EL2 and disabling
traps so lower ELs can access the new registers.

Change the FVP platform to default to handling this as a dynamic option so
the right decision can be made by the code at runtime.

Signed-off-by: Mark Brown <broonie@kernel.org>
Change-Id: I297452acd8646d58bac64fc15e05b06a543e5148
diff --git a/include/lib/el3_runtime/aarch64/context.h b/include/lib/el3_runtime/aarch64/context.h
index 40bfa39..31d8f07 100644
--- a/include/lib/el3_runtime/aarch64/context.h
+++ b/include/lib/el3_runtime/aarch64/context.h
@@ -229,6 +229,9 @@
 // Register for FEAT_HCX
 #define CTX_HCRX_EL2            U(0x1d0)
 
+// Starting with Armv8.9
+#define CTX_TCR2_EL2            U(0x1d8)
+
 /* Align to the next 16 byte boundary */
 #define CTX_EL2_SYSREGS_END	U(0x1e0)