lima/ppir: fix lod bias src
ppir has some code that operates on all ppir_src variables, and for that uses ppir_node_get_src. lod bias support used a separate ppir_src that is inaccessible by that function, causing it to be missed by the compiler. Ultimately this caused a bug in const lowering in some cases:
.../pp/lower.c:42: ppir_lower_const: Assertion `src != NULL' failed.
This fix moves the ppir_src in ppir_load_texture_node together so they don't get missed.
Fixes: 721d82cf lima/ppir: add lod-bias support