libsdl2: add back xvm and xinerama options

libsdl2: add back xvm and xinerama options

When building libsdl2-native, and I met a do_configure error as below.

  | CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
  | Please set them or make sure they are set and tested correctly in the CMake files:
  | XINERAMA_LIB

This error appears on hosts with libxinerama-dev installed.

Looking at the CMakeLists.txt file, I got:

  set(SDL_X11_OPTIONS Xcursor Xdbe Xinerama XInput Xfixes Xrandr Xscrnsaver XShape Xvm

We an see neither Xinerama nor Xvm is removed. So we should add back
these options removed by a previous commit.

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>