ARM: davinci: ensure global variables are declared

Fix the following sparse warnings by declaring relevant
global variables.

  CHECK   arch/arm/mach-davinci/usb.c
arch/arm/mach-davinci/usb.c:134:12: warning: symbol 'da8xx_register_usb20' was not declared. Should it be static?
arch/arm/mach-davinci/usb.c:169:12: warning: symbol 'da8xx_register_usb11' was not declared. Should it be static?

  CHECK   arch/arm/mach-davinci/pm.c
arch/arm/mach-davinci/pm.c:155:12: warning: symbol 'davinci_pm_init' was not declared. Should it be static?
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/mach-davinci/pm.c

@@ -19,6 +19,7 @@
 #include <asm/delay.h>
 #include <asm/io.h>
 
+#include <mach/common.h>
 #include <mach/da8xx.h>
 #include <mach/sram.h>
 #include <mach/pm.h>

arch/arm/mach-davinci/usb.c

@@ -10,6 +10,7 @@
 #include <mach/common.h>
 #include <mach/irqs.h>
 #include <mach/cputype.h>
+#include <mach/da8xx.h>
 #include <linux/platform_data/usb-davinci.h>
 
 #define DAVINCI_USB_OTG_BASE	0x01c64000