qemuarm-efi.conf: Introduce qemuarm machine equivalent with EFI

This machine is based on Cortex-A15 with softfp (to avoid hacks on grub
side as it requires softfp or a way to force flag to softfp). For the
EFI side, it uses edk2-firmware.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>
Signed-off-by: Luca Seritan <luca.seritan@huawei.com>