sdl_glimp: fix the EXT/ARB texture_rg confusion

Author: illwieckz

src/engine/sys/sdl_glimp.cpp

@@ -2025,14 +2025,14 @@ static void GLimp_InitExtensions()
 	Cvar::Latch( r_arb_shader_storage_buffer_object );
 	Cvar::Latch( r_arb_sync );
 	Cvar::Latch( r_arb_texture_gather );
+	Cvar::Latch( r_arb_texture_rg );
 	Cvar::Latch( r_arb_uniform_buffer_object );
 	Cvar::Latch( r_arb_vertex_attrib_binding );
 	Cvar::Latch( r_ext_draw_buffers );
 	Cvar::Latch( r_ext_gpu_shader4 );
 	Cvar::Latch( r_ext_texture_filter_anisotropic );
 	Cvar::Latch( r_ext_texture_float );
 	Cvar::Latch( r_ext_texture_integer );
-	Cvar::Latch( r_ext_texture_rg );
 	Cvar::Latch( r_ext_texture_srgb_r8 );
 	Cvar::Latch( r_khr_debug );
 	Cvar::Latch( r_khr_shader_subgroup );
@@ -2143,7 +2143,7 @@ static void GLimp_InitExtensions()
 	  && glConfig.gpuShader4Available;
 
 	// made required in OpenGL 3.0
-	glConfig.textureRGAvailable = LOAD_EXTENSION_WITH_TEST( ExtFlag_CORE, ARB_texture_rg, r_ext_texture_rg.Get() );
+	glConfig.textureRGAvailable = LOAD_EXTENSION_WITH_TEST( ExtFlag_CORE, ARB_texture_rg, r_arb_texture_rg.Get() );
 
 	{
 		bool textureGatherEnabled = r_arb_texture_gather.Get();