meson: install khrplatform header for EGL as well as GLES

Signed-off-by: Dylan Baker <dylanx.c.baker@intel.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

include/meson.build

@@ -40,7 +40,7 @@ if with_gles2
   )
 endif
 
-if with_gles1 or with_gles2 # or with_egl
+if with_gles1 or with_gles2 or with_egl
   install_headers('KHR/khrplatform.h', subdir : 'KHR')
 endif