ARM: OMAP: Fix warning about missing clk_get_usecount() declaration

arch/arm/plat-omap/clock.c exports clk_get_usecount(), but linux/clk.h
doesn't contain the prototype for it. Add it to asm/arch/clock.h and add
clock.h to omap-audio-aic23.c.
sound/oss/omap-audio-aic23.c: In function clk_get_usecount'

Signed-off-by: Dirk Behme <dirk.behme_at_de.bosch.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

include/asm-arm/arch-omap/clock.h

@@ -57,6 +57,7 @@ extern void propagate_rate(struct clk *clk);
 extern void followparent_recalc(struct clk * clk);
 extern void clk_allow_idle(struct clk *clk);
 extern void clk_deny_idle(struct clk *clk);
+extern int clk_get_usecount(struct clk *clk);
 
 /* Clock flags */
 #define RATE_CKCTL		(1 << 0)	/* Main fixed ratio clocks */

sound/oss/omap-audio-aic23.c

@@ -47,6 +47,7 @@
 #include <asm/arch/mcbsp.h>
 #include <asm/arch/fpga.h>
 #include <asm/arch/aic23.h>
+#include <asm/arch/clock.h>
 
 #include "omap-audio.h"
 #include "omap-audio-dma-intfc.h"