Fix SDL include path.

Fix SDL include path.

SDL header files can be included in two different ways:

* like this: #include <SDL/SDL.h>
* like this: #include <SDL.h>

The 1st alternative is simple and works in many cases.

The 2nd alternative needs sdl-config to get the
correct compiler flags. It is the recommended way
to write SDL includes and standard for QEMU.

The patch fixes two non-standard SDL includes.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>