[MTD ONENAND] Remove unused MTD_ONENAND_SYNC_READ configuration
Now the bootloader configures the OneNAND sync. burst mode.
So we don't access Sync. burst mode related registers in kernel.
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>