Revert "Fix #3246"

This reverts commit e4dcbd518091a5854a517ea4cfc3f7e2d29de1a7.

src/rlgl.h

@@ -2945,7 +2945,6 @@ bool rlCheckRenderBatchLimit(int vCount)
 unsigned int rlLoadTexture(const void *data, int width, int height, int format, int mipmapCount)
 {
     unsigned int id = 0;
-    if (data == NULL) return id;
 
     glBindTexture(GL_TEXTURE_2D, 0);    // Free any old binding