feat(mediatek): move plat_helpers.h to the common folder

The plat_helpers.h is identical across various platforms, moved to the
common folder for easier maintenance.

Change-Id: Ic9f10c697fcda7e3cfbf32e67486c9cd28481b8a
diff --git a/plat/mediatek/mt8188/include/plat_helpers.h b/plat/mediatek/include/plat_helpers.h
similarity index 71%
rename from plat/mediatek/mt8188/include/plat_helpers.h
rename to plat/mediatek/include/plat_helpers.h
index eb78623..b86ed23 100644
--- a/plat/mediatek/mt8188/include/plat_helpers.h
+++ b/plat/mediatek/include/plat_helpers.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2024, Mediatek Inc. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
diff --git a/plat/mediatek/mt8186/include/plat_helpers.h b/plat/mediatek/mt8186/include/plat_helpers.h
deleted file mode 100644
index ebc9fa0..0000000
--- a/plat/mediatek/mt8186/include/plat_helpers.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#ifndef __PLAT_HELPERS_H__
-#define __PLAT_HELPERS_H__
-
-unsigned int plat_mediatek_calc_core_pos(u_register_t mpidr);
-
-#endif /* __PLAT_HELPERS_H__ */
diff --git a/plat/mediatek/mt8192/include/plat_helpers.h b/plat/mediatek/mt8192/include/plat_helpers.h
deleted file mode 100644
index 9b550ee..0000000
--- a/plat/mediatek/mt8192/include/plat_helpers.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Copyright (c) 2020, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#ifndef __PLAT_HELPERS_H__
-#define __PLAT_HELPERS_H__
-
-unsigned int plat_mediatek_calc_core_pos(u_register_t mpidr);
-
-#endif /* __PLAT_HELPERS_H__ */
diff --git a/plat/mediatek/mt8195/include/plat_helpers.h b/plat/mediatek/mt8195/include/plat_helpers.h
deleted file mode 100644
index ebc9fa0..0000000
--- a/plat/mediatek/mt8195/include/plat_helpers.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
-
-#ifndef __PLAT_HELPERS_H__
-#define __PLAT_HELPERS_H__
-
-unsigned int plat_mediatek_calc_core_pos(u_register_t mpidr);
-
-#endif /* __PLAT_HELPERS_H__ */