i915g: Stop translating the fragment program on the first error.

It would proceed through printing errors for each of the unsupported loop
opcodes in the program.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11617>

src/gallium/drivers/i915/i915_fpc_translate.c

@@ -914,7 +914,7 @@ i915_translate_instructions(struct i915_fp_compile *p,
                             struct i915_fragment_shader *fs)
 {
    int i;
-   for (i = 0; i < tokens->NumTokens; i++) {
+   for (i = 0; i < tokens->NumTokens && !p->error; i++) {
       i915_translate_token(p, &tokens->Tokens[i], fs);
    }
 }