lmb: use the BIT macro for lmb flags

lmb: use the BIT macro for lmb flags

Use the BIT macro for assigning values to the LMB flags instead of
assigning random values to them.

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>