sh: hd64461: Make setup_hd64461() static

Enforce internal linkage for setup_hd64461().

This fixes the following error:
arch/sh/cchips/hd6446x/hd64461.c:75:12: error: no previous prototype for 'setup_hd64461' [-Werror=missing-prototypes]

Signed-off-by: Artur Rojek <[e-mail]>
Reviewed-by: John Paul Adrian Glaubitz <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: John Paul Adrian Glaubitz <[e-mail]>

arch/sh/cchips/hd6446x/hd64461.c

···
 	}
 }
 
-int __init setup_hd64461(void)
+static int __init setup_hd64461(void)
 {
 	int irq_base, i;