mtd: fsmc: use ALE and CLE offsets from platform data

ALE and CLE offsets can be different on different devices. Let devices
pass these offsets to the fsmc driver through platform data.

Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>