hikey960: BoardConfig.mk: Remove legacy dtb fstab logic

The dtb fstab logic is no longer supported, and was
getting triggered only with 4.14 kernels which caused
problems trying to boot with the virt-a/b config we've
used for awhile.

So drop this logic entirely to clean things up.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: Id9f9dfc58225cfbad9ef666b8e917feed5325292
1 file changed