tizen: add default dfu macros

tizen: add default dfu macros

There is CONFIG_SET_DFU_ALT_INFO, but CONFIG_DFU_ALT_BOOT_EMMC is not
set, and it causes build error for usbdown and nfsdown commands.
Add default dfu macros, CONFIG_DFU_ALT_BOOT_EMMC and
CONFIG_DFU_ALT_BOOT_SD to tizen.h which is used odroid-u3 family and
trats2 boards.
The usbdown and nfsdown commands are only possible on odroid-u3
family boards, so default dfu macros are set as odroid dfu macro.

Change-Id: Ic6ea1549492a073b6434e20f7ffcf329475f6670
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>