swiotlb-xen: drop leftover __ref

Commit a98f5654 ("xen-swiotlb: split xen_swiotlb_init") should not
only have added __init to the split off function, but also should have
dropped __ref from the one left.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Link: https://lore.kernel.org/r/7cd163e1-fe13-270b-384c-2708e8273d34@suse.comSigned-off-by: Juergen Gross <jgross@suse.com>

drivers/xen/swiotlb-xen.c

@@ -154,7 +154,7 @@ static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
 
 #define DEFAULT_NSLABS		ALIGN(SZ_64M >> IO_TLB_SHIFT, IO_TLB_SEGSIZE)
 
-int __ref xen_swiotlb_init(void)
+int xen_swiotlb_init(void)
 {
 	enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
 	unsigned long bytes = swiotlb_size_or_default();