[coreboot] small bug/typo in libpayload

[Roman Yeryomin]

If you do not include "See output on a video console" 
it falls out with error

  AS      build/i386/head.S.o
  CC      build/i386/main.o
  CC      build/i386/sysinfo.o
  CC      build/i386/timer.o
  CC      build/i386/coreboot.o
  AS      build/i386/util.S.o
  AS      build/i386/exec.S.o
  CC      build/i386/virtual.o
  CC      build/crypto/sha1.o
  CC      build/libc/malloc.o
  CC      build/libc/printf.o
  CC      build/libc/console.o
  CC      build/libc/string.o
  CC      build/libc/memory.o
  CC      build/libc/ctype.o
  CC      build/libc/ipchecksum.o
  CC      build/libc/lib.o
  CC      build/libc/rand.o
  CC      build/libc/time.o
  CC      build/libc/lar.o
  CC      build/libc/exec.o
  CC      build/libc/readline.o
  CC      build/drivers/pci.o
  CC      build/drivers/speaker.o
  CC      build/drivers/serial.o
  CC      build/drivers/keyboard.o
  CC      build/drivers/nvram.o
  CC      build/drivers/options.o
  CC      build/curses/keyboard.o
  CC      build/curses/tinycurses.o
cc1: warnings being treated as errors
/home/wiz/dev/coreboot/libpayload-r/curses/tinycurses.c: In 
function ‘wnoutrefresh’:
/home/wiz/dev/coreboot/libpayload-r/curses/tinycurses.c:739: warning: unused 
variable ‘c’
make: *** [/home/wiz/dev/coreboot/libpayload-r/build/curses/tinycurses.o] 
Error 1

this can be fixed with including 
unsigned int c = ((int)color_pairs[PAIR_NUMBER(attr)]) << 8;
in #ifdef CONFIG_VIDEO_CONSOLE like this:

#ifdef CONFIG_VIDEO_CONSOLE
            unsigned int c = ((int)color_pairs[PAIR_NUMBER(attr)]) << 8;
#endif


Regards,
Roman