feat(spm): separate StMM SP specifics to add support for a S-EL0 SP

This patch separates the code from SPM_MM to get xlat table context and
move it to a common location. In addition, only APIs required from both
SPM_MM and FF-A EL3 SPMC are moved to the common location.

This allows understanding better what is required to support a S-EL0 SP
instead of trying to retrofit what already exists.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: I142d7fbef5239869176d0de93842c66051d7ed78
diff --git a/services/std_svc/spm/spm_mm/spm_mm_private.h b/services/std_svc/spm/spm_mm/spm_mm_private.h
index 0eff1c0..3a52a3e 100644
--- a/services/std_svc/spm/spm_mm/spm_mm_private.h
+++ b/services/std_svc/spm/spm_mm/spm_mm_private.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2022, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2023, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -55,8 +55,6 @@
 
 void spm_sp_setup(sp_context_t *sp_ctx);
 
-xlat_ctx_t *spm_get_sp_xlat_context(void);
-
 int32_t spm_memory_attributes_get_smc_handler(sp_context_t *sp_ctx,
 					      uintptr_t base_va);
 int spm_memory_attributes_set_smc_handler(sp_context_t *sp_ctx,