PIC32MZ: Changes that will permit building of the PIC32MZ Start Kit configuration using MPLAB and the XC32 toolchain.  From David Sidrane

Extend the AT24 EEPROM driver so that it supports: (1) the byte-oriented read() method, (2) parts with extended memory regions, and (3) parts with 8-bit addressing.

SAMV7: Quick'n'dirty port of the SAMA5D4 Ethernet MAC driver to the SAMV7.  Still some unresovled issues with DCache handling

This commit enables HSMCI functionality in the SAMV71-XULT.  TX DMA is, unfortunately, currently disabled.

SAMA5:  Fix a bug in SAMA5 HSMCI.  The bitfield mask and shift values were reversed resulting in a trashed value for the number of blocks in the BLOCKR register.  This was sufficient to prevent DMA writes from working.

Fix some bad logic when file system debug is turned on:  Arguments to syslog were missing so that garbage was being printed.

Fix a bug in the FAT unbind() logic.  There were problems with the way certain internal list handling was implemented.  The end result is that newly opened or cloned file structures were never being added to the list of open files.  So when the unmount() happens, it always looked like there were not open files and a crash could ensue.

Pass the umount2() flags to every unbind() implementation.  That is where the the decision to umount or not will be made.