chore(spm): change spm out dir

Hafnium is now built with the VHE build option set by default.
As a result, the output directory from which retrieve the
Hafnium binary needs changing.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I1fa4a1a0bfa8f589478404e7b7c8e3c4040cbe11
2 files changed