Accton platforms onie syseeprom

Part 1: (the patches are move to pull request #63)
busybox.make and i2ctools.make will raise an error message if the machine patch directory has no any .patch file.  I revise those Makefiles to make them be consistent with the one in kernel.make

    ==== Patching Busybox ====
    cp: cannot stat `../machine/accton/accton_as6712_32x/busybox/*.patch': No such file or directory
    make: *** [/public/david/onie/onie-accton/build/accton_as6712_32x-r0/stamp/busybox-patch] Error 1

Part 2:
Migrate the support of onie-syseeprom from i2ctools to busybox for Accton Platforms.