ti-gfx: use only -I${includedir} as pkg-config Cflags

Using only -I${includedir} in common practice.

Settings only -I${includedir}/GLES2 breaks Qt5's CMake files,
because at configure time CMake only searchs the paths reported
by pkg-config, and not even /usr/include is used as default.

Even though pkg-config strips out standard include path, that's not
the case with pkgconf (which we are using) in cross-compilation,
which correctly reports the /usr/include dir prefixed with the
sysroot.

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Kümmel <syntheticpp@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/ti-gfx/egl.pc

@@ -8,4 +8,4 @@ Description: TI Graphics SDK implementation of EGL
 Version: 1.9.2188537
 Requires:
 Libs: -L${libdir} -lEGL -lGLESv2 -lIMGegl
-Cflags: -I${includedir}/EGL/ -I${includedir}
+Cflags: -I${includedir}

package/ti-gfx/glesv2.pc

@@ -8,4 +8,4 @@ Description: TI Graphics SDK implementation of OpenGL ESv2
 Version: 1.9.2188537
 Requires:
 Libs: -L${libdir} -lGLESv2 -lGLES_CM -lsrv_um -lusc -lEGL -lIMGegl
-Cflags: -I${includedir}/GLES2
+Cflags: -I${includedir}