Update UHD to 4.7.0

Compile-from-source-in-Linux.md

@@ -278,7 +278,7 @@ Prerequisites:
 <pre><code>cd /opt/build
 git clone https://github.com/EttusResearch/uhd.git
 cd uhd
-git reset --hard v4.5.0.0
+git reset --hard v4.7.0.0
 cd host
 mkdir build
 cd build