Update git submodules

* Update trusty/device/arm/generic-arm64 from branch 'master'
  to 5fb6aa68b7c6cc694eb3eb142a71c98d4dac351f
  - [project][linux] Link Linux with LLD
    
    32-bit kernel can no longer be linked with gold after patch
    "kbuild: Fail if gold linker is detected"
    https://lkml.org/lkml/2019/7/16/635
    
    Move all Linux builds to LLD while we're at it.
    
    Bug: None
    Change-Id: I713e55914e09d4c09afd956899869dacaa95824c
    
diff --git a/trusty/device/arm/generic-arm64 b/trusty/device/arm/generic-arm64
index 2631689..5fb6aa6 160000
--- a/trusty/device/arm/generic-arm64
+++ b/trusty/device/arm/generic-arm64
@@ -1 +1 @@
-Subproject commit 26316899e5c1a057e756a2f3dcaec984cd025d63
+Subproject commit 5fb6aa68b7c6cc694eb3eb142a71c98d4dac351f