Add a function to flatten out the addresses of the flash chip as per the
different erase functions. This function will return a list of layouts
which is dynamically allocated. So after use all the layouts as well as
the list itself should be freed. The free_erase_layout function does
that.
Change-Id: Iafe78de00daa55f7114bd4ce09465dd88074ece4
Signed-off-by: Aarya Chaumal <aarya.chaumal@gmail.com>