bpf: Disasm support for addr_space_cast instruction.

LLVM generates rX = addr_space_cast(rY, dst_addr_space, src_addr_space)
instruction when pointers in non-zero address space are used by the bpf
program. Recognize this insn in uapi and in bpf disassembler.

Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Kumar Kartikeya Dwivedi <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

include/uapi/linux/bpf.h

@@ -1339,6 +1339,10 @@ enum {
  */
 #define BPF_PSEUDO_KFUNC_CALL	2
 
+enum bpf_addr_space_cast {
+	BPF_ADDR_SPACE_CAST = 1,
+};
+
 /* flags for BPF_MAP_UPDATE_ELEM command */
 enum {
 	BPF_ANY		= 0, /* create new element or update existing */