s5j/sflash: fix a link error

s5j/sflash: fix a link error

This commit fixes a link error that occurs on a specific combination of
configurations.

    /home/heesub/Documents/artik053/tizenrt/os/../build/output/libraries/libarch.a(s5j_sflash.o): In function `s5j_sflash_init':
    /home/heesub/Documents/artik053/tizenrt/os/arch/arm/src/chip/s5j_sflash.c:258: undefined reference to `lldbg'
    Makefile:187: recipe for target '../build/output/bin/tinyara' failed

Change-Id: I76047db6d86a2c244f245ba52380b45118ddb981
Signed-off-by: Heesub Shin <heesub.shin@samsung.com>