Fix:
cpuinfo.c: In function 'print_cpuinfo':
cpuinfo.c:155:6: warning: variable 'system_serial_low' set but not used
[-Wunused-but-set-variable]
cpuinfo.c:154:6: warning: variable 'system_serial_high' set but not used
[-Wunused-but-set-variable]
Signed-off-by: Anatolij Gustschin <agust@denx.de>
 
 #include <common.h>
 #include <command.h>
+#include <linux/compiler.h>
 
 #if defined(CONFIG_DISPLAY_CPUINFO) && defined(CONFIG_OMAP)
 
        u8 die_rev;
        u32 omap_id;
        u8 cpu_type;
-       u32 system_serial_high;
-       u32 system_serial_low;
+       __maybe_unused u32 system_serial_high;
+       __maybe_unused u32 system_serial_low;
        u32 system_rev = 0;
 
        jtag_id = omap_get_jtag_id();