aarch64: Enable Statistical Profiling Extensions for lower ELs

SPE is only supported in non-secure state.  Accesses to SPE specific
registers from SEL1 will trap to EL3.  During a world switch, before
`TTBR` is modified the SPE profiling buffers are drained.  This is to
avoid a potential invalid memory access in SEL1.

SPE is architecturally specified only for AArch64.

Change-Id: I04a96427d9f9d586c331913d815fdc726855f6b0
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
diff --git a/include/lib/el3_runtime/aarch64/context.h b/include/lib/el3_runtime/aarch64/context.h
index dead971..dcbf1c9 100644
--- a/include/lib/el3_runtime/aarch64/context.h
+++ b/include/lib/el3_runtime/aarch64/context.h
@@ -308,6 +308,7 @@
  * Function prototypes
  ******************************************************************************/
 void el1_sysregs_context_save(el1_sys_regs_t *regs);
+void el1_sysregs_context_save_post_ops(void);
 void el1_sysregs_context_restore(el1_sys_regs_t *regs);
 #if CTX_INCLUDE_FPREGS
 void fpregs_context_save(fp_regs_t *regs);