* Remove CONFIG_CLOCKSOURCE_EFI configuration
It seems to cause messages like this on some machines:
EFI Event timer too slow freq = 100 Hz
The Barebox efi_defconfig configurationd doesn't enable it either.
Disable it by default as well.
* Enable CONFIG_CMD_ECHO_E to fix menutree
It seems that menutree needs CONFIG_CMD_ECHO_E to properly display the
boot menu.
Also enable other useful commands such as edit or reset.
* Bump Barebox to 2021.05.0
When booting the HassOS VMDK appliance disk image on QEMU with OVMF UEFI
firmware, barebox numbers devices differently from other environments.
This patch makes the barebox `sh` implementation expand a pathname
wildcard at runtime, so that assigned disk indices != 0 will also work.
This fix introduces a potential (but most likely irrelevant)
bug/problem: If there is more than one disk connected to the system with
a matching name assigned, the wildcard will expand to two or more
pathnames, breaking the resulting `mount` command.
