Rename CONFIG_ARMV7M_MPU to CONFIG_ARM_MPU so that we can reuse the configuration settings for the ARMV7R MPU

SAMV71-XULT: module configuration.  Module cannot link with libc because it has out-of-range function calls

Add CONFIG_ARCH_BOARD_CUSTOM_DIR_RELPATH

Refresh all configurations that have Telnetd enabled; those configurations now also need the telnet driver

Remove CONFIG_NET_PINGADDRCONF.  This was a uIP way of assigning IP addresses, but is not standard and not a appropriate feature in general.

SAME70:  Initialization has to be done a little differently because the board has no 32.768KHz crystal installed

SAME70 Xplained: Refresh configuration, enable PROCFS.  Add logic to automatically mount procfs during initialization

Move up_appinit.c to configs/sim/src where it belongs.  Add logic to automatically mount the procfs file system if it is enabled.

All SAMA5 configurations: Refresh configurations, enable PROCFS in all configurations that have CONFIG_NSH_LIBRARY=y, add logic to automatically mount the procfs if it is enabled