build: Clear out remaining compile warnings. (#6662)

src/video_core/host_shaders/format_reinterpreter/d24s8_to_rgba8.frag

@@ -4,6 +4,9 @@
 
 //? #version 430 core
 
+precision highp int;
+precision highp float;
+
 layout(location = 0) in mediump vec2 tex_coord;
 layout(location = 0) out lowp vec4 frag_color;
 

src/video_core/host_shaders/format_reinterpreter/rgba4_to_rgb5a1.frag

@@ -4,6 +4,9 @@
 
 //? #version 430 core
 
+precision highp int;
+precision highp float;
+
 layout(location = 0) in mediump vec2 tex_coord;
 layout(location = 0) out lowp vec4 frag_color;