powerpc/boot: remove unused function find_node_by_linuxphandle()

The last user of find_node_by_linuxphandle() was removed in v4.18-rc1
by commit 30f4bbe0 ("powerpc/boot: Remove support for Marvell MPSC serial controller")
four years ago.  This function is no longer needed.
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220424184014.968274-1-frowand.list@gmail.com

arch/powerpc/boot/ops.h

@@ -200,12 +200,6 @@ void __dt_fixup_mac_addresses(u32 startindex, ...);
 	__dt_fixup_mac_addresses(0, __VA_ARGS__, NULL)
 
 
-static inline void *find_node_by_linuxphandle(const u32 linuxphandle)
-{
-	return find_node_by_prop_value(NULL, "linux,phandle",
-			(char *)&linuxphandle, sizeof(u32));
-}
-
 static inline char *get_path(const void *phandle, char *buf, int len)
 {
 	if (dt_ops.get_path)