Dep: Update golang dep to support Arm64
Dep: Update golang dep to support Arm64

Current Rook code uses go dep 0.5.0 and separates handling
for Arm and x86. It's because there's no dep 0.5.0 binary
for arm64.Dep has updated to 0.5.4 and supports arm64. Rook
code can be simplified by upgrading dep to fix gaps of Arm
and x86.

Change-Id: Id91a993ca059461faa8a83065c93dadc7cdffeb2
Signed-off-by: Haichao Li <37f5482d95cefe2bab13c62ae3603147a6ba3fd0@arm.com>

rook/rook,rook/rook,rook/rook,rook/rook,rook/nfs,rook/rook,rook/nfs,rook/nfs