Add const to function declaration. Const objects cannot access const
safe functions, a compiler error is thrown if one tries to do so. This
helps ensure that the object calling the method will not be modified.
This is espescially desirable in functions where all we need to do is
query existing data and not make any alterations.
[Q/O/SPIFBlockDevice::erase() begin with an alignment check,
after which unaligned erases should not happen or be allowed.
If the erase address is not aligned to the value returned by
sfdp_iterate_next_largest_erase_type(), it indicates an
internal error in erase table parsing which should not be
hidden.
The first revision (1.0) of SFDP (ref: JESD216) does not include
fields for software reset support. It's only been added in the
second revision (1.5) (ref: JESD216A).
Some Mbed OS targets such as DISCO_F746NG include flashes with
legacy SFDP, thus we add an option to preset the reset mode.