x86: baytrail: Change lpe/lpss-sio/scc FSP properties to integer

At present lpe/lpss-sio/scc FSP properties are all boolean, but in
fact for "enable-lpe" it has 3 possible options. This adds macros
for these options and change the property from a boolean type to
an integer type, and change their names to explicitly indicate what
the property is really for.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>