examples: add fallback memcpy

Solves build issue:

  Building current source for 134 boards (12 threads, 1 job per thread)
         arm:  +   lsxhl
  +examples/api/vsprintf.o: In function `string16':
  +lib/vsprintf.c:278: undefined reference to `memcpy'
  +examples/api/uuid.o: In function `uuid_bin_to_str':
  +lib/uuid.c:197: undefined reference to `memcpy'
  +lib/uuid.c:199: undefined reference to `memcpy'
  +make[3]: *** [examples/api/demo] Error 1
  +make[2]: *** [examples/api] Error 2
  +make[1]: *** [examples] Error 2
  +make: *** [sub-make] Error 2
    133    0    1 /134    sheevaplug

Signed-off-by: Rob Clark <robdclark@gmail.com>