Add trim to shell command

Change-Id: I74288e708d7e02d723939b341f0ab5c186263ca7
diff --git a/vars/functions.groovy b/vars/functions.groovy
index 4cf4a6f..d092a7d 100644
--- a/vars/functions.groovy
+++ b/vars/functions.groovy
@@ -37,7 +37,7 @@
 }
 
 def buildTarget(targetName) {
-    def nprocs = sh(returnStdout: true, script: 'nproc')
+    def nprocs = sh(returnStdout: true, script: 'nproc').trim()
     sh "bash -c 'source build/setup.sh; m -j${nprocs} prereqs ${targetName}; exit \$?'"
 }