efi_loader: update virtual address in efi_mem_carve_out

Handle virtual address in efi_mem_carve_out() function
when a new region is created to avoid issue in EFI memory map.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>

At boottime physical and virtual addressed have to be the same.
This allowed to simplify the proposed logic.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>