[client] egl: remove needless precision quantifiers

We simply use precision mediump float; for everything. We don't actually
need highp anyways, and we don't use it for stuff like CAS or FSR.

client/renderers/EGL/shader/cursor_rgb.frag

@@ -1,13 +1,13 @@
 #version 300 es
+precision mediump float;
 
 #include "color_blind.h"
 
-in  highp vec2 uv;
-out highp vec4 color;
+in  vec2 uv;
+out vec4 color;
 
 uniform sampler2D sampler1;
 
-uniform lowp int rotate;
 uniform int cbMode;
 
 void main()