Android: fix build break in libmesa_program

Commit 5fd848f6c9 ("program: Use _mesa_geometric_samples to calculate
gl_NumSamples") broken Android builds. Add the missing include path "main"
to framebuffer.h like other includes in prog_statevars.c.

Cc: Neil Roberts <neil@linux.intel.com>
Cc: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

src/mesa/program/prog_statevars.c

@@ -40,7 +40,7 @@
 #include "prog_statevars.h"
 #include "prog_parameter.h"
 #include "main/samplerobj.h"
-#include "framebuffer.h"
+#include "main/framebuffer.h"
 
 
 #define ONE_DIV_SQRT_LN2 (1.201122408786449815)