sh: Disable get_dma_error_irq for non-SH4 targets.

dma-sh's get_dma_error_irq() is only used by SH4, as the SH3
doesn't have the DMA Error interrupt.

Disable it out for non-SH4 builds.
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/drivers/dma/dma-sh.c

@@ -280,6 +280,7 @@ static struct dma_info sh_dmac_info = {
 	.flags		= DMAC_CHANNELS_TEI_CAPABLE,
 };
 
+#ifdef CONFIG_CPU_SH4
 static unsigned int get_dma_error_irq(int n)
 {
 #if defined(DMAC_IRQ_MULTI)
@@ -293,6 +294,7 @@ static unsigned int get_dma_error_irq(int n)
 #endif
 #endif
 }
+#endif
 
 static int __init sh_dmac_init(void)
 {