OMAP2+: voltage: split voltage controller (VC) code into dedicated layer

As part of the voltage layer cleanup, split out VC specific code into
a dedicated VC layer.  This patch primarily just moves VC code from
voltage.c into vc.c, and adds prototypes to vc.h.

No functional changes.

For readability, each function was given a local 'vc' pointer:

    struct omap_vc_instance_data *vc = voltdm->vdd->vc_data;

and a global replace of s/vdd->vc_data/vc/ was done.

Also vc_init was renamed to vc_init_channel to reflect that this is
per-VC channel initializtion.

Signed-off-by: Kevin Hilman <khilman@ti.com>
diff --git a/arch/arm/mach-omap2/vc.h b/arch/arm/mach-omap2/vc.h
index f7338af..d0bf348 100644
--- a/arch/arm/mach-omap2/vc.h
+++ b/arch/arm/mach-omap2/vc.h
@@ -19,6 +19,8 @@
 
 #include <linux/kernel.h>
 
+struct voltagedomain;
+
 /**
  * struct omap_vc_common_data - per-VC register/bitfield data
  * @cmd_on_mask: ON bitmask in PRM_VC_CMD_VAL* register
@@ -81,5 +83,15 @@
 extern struct omap_vc_instance_data omap4_vc_iva_data;
 extern struct omap_vc_instance_data omap4_vc_core_data;
 
+void omap_vc_init_channel(struct voltagedomain *voltdm);
+int omap_vc_pre_scale(struct voltagedomain *voltdm,
+		      unsigned long target_volt,
+		      u8 *target_vsel, u8 *current_vsel);
+void omap_vc_post_scale(struct voltagedomain *voltdm,
+			unsigned long target_volt,
+			u8 target_vsel, u8 current_vsel);
+int omap_vc_bypass_scale_voltage(struct voltagedomain *voltdm,
+				 unsigned long target_volt);
+
 #endif