ARM: OMAP2+: CM: prepare for use of cm_ll_data function pointers

There are several CM operations which behave similarly across OMAP2+
SoCs, but which have slight differences in their underlying
implementations.

This patch creates the support code for this function pointer
registration process.  No function pointers are included yet, but a
subsequent patch will create these for the module IDLEST registers.

This patch allows other code to use CM-provided data and operations
without needing to know which SoC is currently in use.  A further
description of the concept is provided in the patch entitled
"ARM: OMAP2+: PRM: prepare for use of prm_ll_data function pointers".

Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap2/cm.h

@@ -33,4 +33,16 @@
  */
 #define MAX_MODULE_DISABLE_TIME		5000
 
+# ifndef __ASSEMBLER__
+
+/**
+ * struct cm_ll_data - fn ptrs to per-SoC CM function implementations
+ */
+struct cm_ll_data {};
+
+extern int cm_register(struct cm_ll_data *cld);
+extern int cm_unregister(struct cm_ll_data *cld);
+
+# endif
+
 #endif