meta-oe, meta-efl: Restore few MIRROR variables

* these were correctly removed from oe-core in
  commit 3b333896c71689c664475d53daed52404bf6b21b
  Author: Phil Blundell <pb@pbcl.net>
  Date:   Thu Nov 14 18:15:46 2013 +0000

    bitbake.conf: Remove obsolete/unused MIRROR cruft
  but we still need them here, so add them to layer.conf

* FREESMARTPHONE_GIT is used by 4 recipes in meta-oe and a lot more in meta-fso (which depends on meta-oe)
  meta-oe/recipes-devtools/vala-dbus-binding-tool/vala-dbus-binding-tool_git.bb:SRC_URI = "${FREESMARTPHONE_GIT}/vala-dbus-binding-tool.git;branch=master"
  meta-oe/recipes-support/serial-utils/pty-forward-native.bb:SRC_URI = "${FREESMARTPHONE_GIT}/cornucopia"
  meta-oe/recipes-support/serial-utils/serial-forward_git.bb:SRC_URI = "${FREESMARTPHONE_GIT}/cornucopia"
  meta-oe/recipes-support/vala-terminal/vala-terminal_git.bb:SRC_URI = "${FREESMARTPHONE_GIT}/vala-terminal.git;branch=master"

* E_MIRROR/E_SVN are used in many recipes in meta-efl, even with
  upstream moveing to git, not all components are already in git
  and for distros with populated PREMIRROR these variables are still
  important to parse the recipes.

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>

meta-oe/conf/layer.conf

@@ -33,3 +33,5 @@ SIGGEN_EXCLUDERECIPES_ABISAFE += " \
   distro-feed-configs \
   ca-certificates \
 "
+
+FREESMARTPHONE_GIT = "git://git.freesmartphone.org"