[PATCH 0/4 v2] mtd: physmap_of: Add multiple regions and concatenation support

This patchset adds support to handle multiple non-identical chips in one
flash device tree node. It also adds concat support to physmap_of. This
makes it possible to support e.g. the Intel P30 48F4400 chip which
internally consists of 2 non-identical NOR chips on one die. Additionally
partitions now can span over multiple chips:

    mtd: physmap_of: Add multiple regions and concatenation support
    mtd/powerpc: Factor out MTD physmap bindings into mtd-physmap.txt
    mtd/powerpc: Remove unused "device-width" property
    mtd/powerpc: Describe multiple "reg" tuples usage

v2 addresses all comments from Grant Likely, including factoring out the
MTD dts bindings documentation into a separate file.

Thanks,
Stefan