[ARM] 5513/1: Eurotech VIPER SBC: fix compilation error

Compilation for this board yields the following errors:

arch/arm/mach-pxa/viper.c:511: error: 'FFUART' undeclared here (not in a function)
arch/arm/mach-pxa/viper.c:520: error: 'BTUART' undeclared here (not in a function)
arch/arm/mach-pxa/viper.c:529: error: 'STUART' undeclared here (not in a function)

Fix them by including the necessary header.
Signed-off-by: NRicardo Martins <rasm@fe.up.pt>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-pxa/viper.c

@@ -46,6 +46,7 @@
 #include <mach/audio.h>
 #include <mach/pxafb.h>
 #include <mach/i2c.h>
+#include <mach/regs-uart.h>
 #include <mach/viper.h>
 
 #include <asm/setup.h>