feat: complete emulated guess' function to init gfx

guest/gfx/gfx_phys.c

 #include "gfx.h"
 
-#include "guest/utils.h"
-#include "guest/pmio.h"
+#include <stdint.h>
 #include "shared/hypercall_params.h"
 
 // --- DEFINE ---
@@ -12,5 +11,9 @@
 
 void gfx_phys_init(uint32_t width, uint32_t height) {
 
-    // TODO:
+    while (*(uint32_t *)REG_GFX_INIT_ST == 42);
+
+    *(uint32_t *)REG_GFX_INIT_CMD = 5;
+    *(uint32_t *)REG_GFX_INIT_DATA = width;
+    *(uint32_t *)REG_GFX_INIT_DATA = height;
 }