i915g: Fix dumping of the FS in batchbuffers.

We have to increment off of the packet header before disassembling (same
as i915c's copy of this code).

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10874>

src/gallium/drivers/i915/i915_debug_fp.c

@@ -319,6 +319,7 @@ i915_disassemble_program(const unsigned * program, unsigned sz)
 
    assert((program[0] & 0x1ff) + 2 == sz);
 
+   program++;
    for (i = 1; i < sz; i += 3, program += 3) {
       unsigned opcode = program[0] & (0x1f << 24);
 

src/gallium/drivers/i915/i915_fpc_translate.c

@@ -1234,6 +1234,7 @@ i915_translate_fragment_program( struct i915_context *i915,
    i915_optimize_free(i_tokens);
 
 #if 0
+   /* XXX: The disasm wants the concatenation of the decl and program. */
    i915_disassemble_program(fs->program, fs->program_len);
 #endif
 }