Make EasyFlash support multiple partation operations with FAL

[eggcar]

Although FAL support multiple partitions for multiple physical flash devices, only one partation could be used when porting FAL to EasyFlash.

EasyFlash uses one static global partation descriptor in ef_port.c or ef_fal_port.c, and the api doesn't support passing different partation names or partation descriptors. This is not flexible enough when we got several flash chips (in-chip and off-chip). Only one partation in one chip could be managed by EF.

One way to solve this with least changes is to modify the ef_port_xxx apis, passing partation descriptor or partation name or something else into it, and each function block (env, iap, log...) passes different partation params to port apis. But this makes EF and FAL couples tighter. A more abstract descriptor might be added in EF implementation.