agx: Add extr instruction to AGX backend

Encoding is similar to bfeil, in particular the immidiate has the
same encoding as BFI_MASK hence its reuse.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20628>

src/asahi/compiler/agx_opcodes.py

@@ -213,6 +213,10 @@ op("bfeil",
       encoding_32 = (0x2E | L, 0x7F | L | (0x3 << 26), 8, _),
       srcs = 3, imms = [BFI_MASK])
 
+op("extr",
+      encoding_32 = (0x2E | (0x1 << 26), 0x7F | L | (0x3 << 26), 8, _),
+      srcs = 3, imms = [BFI_MASK])
+
 op("asr",
       encoding_32 = (0x2E | L | (0x1 << 26), 0x7F | L | (0x3 << 26), 8, _),
       srcs = 2)