tegra: Use const for pinmux_config_pingroup/table()

These two functions don't actually modify their arguments so add a const
keyword.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/include/asm/arch-tegra20/pinmux.h b/arch/arm/include/asm/arch-tegra20/pinmux.h
index 03fa7ca..797e158 100644
--- a/arch/arm/include/asm/arch-tegra20/pinmux.h
+++ b/arch/arm/include/asm/arch-tegra20/pinmux.h
@@ -339,7 +339,7 @@
 void pinmux_set_func(enum pmux_pingrp pin, enum pmux_func func);
 
 /* Set the complete configuration for a pin group */
-void pinmux_config_pingroup(struct pingroup_config *config);
+void pinmux_config_pingroup(const struct pingroup_config *config);
 
 void pinmux_set_tristate(enum pmux_pingrp pin, int enable);
 
@@ -349,6 +349,6 @@
  * @param config	List of config items
  * @param len		Number of config items in list
  */
-void pinmux_config_table(struct pingroup_config *config, int len);
+void pinmux_config_table(const struct pingroup_config *config, int len);
 
 #endif	/* PINMUX_H */