Remove dependency on libmagma.

libmagma is now statically linked into the libvulkan icds.

MA-468 #comment

Test:
nuc:go/magma-tps#L1

Change-Id: I976aa6545f3e20d47b92b319a724d8f9e52bfd0e
diff --git a/loader/BUILD.gn b/loader/BUILD.gn
index c8ef558..e6f5684 100644
--- a/loader/BUILD.gn
+++ b/loader/BUILD.gn
@@ -73,15 +73,7 @@
   ]
 
   deps = [
-    # libvulkan.so doesn't actually depend on libmagma.so. Instead, the
-    # libraries it loads depend on libmagma.so, but those libraries are
-    # loaded from the system rather than from the package. In order for
-    # those library to find libmagma.so, we include a dependency here, which
-    # ensures that libmagma.so is pulled into every package that depends on
-    # libvulkan.so.
-    "//garnet/lib/magma:libmagma",
-
-    # Similarly to libmaga, the loaded libraries depend on the framebuffer
+    # The loaded libraries depend on the framebuffer
     # library to provide their WSI implementation a stable zircon display
     # API.
     # TODO(ZX-2277): Once the display controller API can provide a stable,