cdx: fix build failure due to sysfs 'bus_type' argument needing to be const

Commit 75cff725d956 ("driver core: bus: mark the struct bus_type for
sysfs callbacks as constant") missed at least one case - the CDX bus
driver. Probably because Greg didn't notice the build failure, because
it only ends up being enabled on arm64.

And I missed it during the merge, because while I do arm64 builds these
days, I don't do them in between each pull. So it took a while for me
to notice the breakage, rather than me just fixing it in the driver core
merge that brought this failure case in.

Maybe we should remove the CDX_BUS dependency on arm64 when COMPILE_TEST
is on?

Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Nipun Gupta <[e-mail]>
Cc: Nikhil Agarwal <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/cdx/cdx.c

···
 };
 ATTRIBUTE_GROUPS(cdx_dev);
 
-static ssize_t rescan_store(struct bus_type *bus,
+static ssize_t rescan_store(const struct bus_type *bus,
 			    const char *buf, size_t count)
 {
 	struct cdx_controller *cdx;