ARM: at91: sam9n12: enable kernel uncompress info output

The sam9n12 use the same array usart as sam9x5, add it which will
enable output kernel uncompress info:
---8>---
Uncompressing Linux... done, booting the kernel.
---<8---
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/include/mach/uncompress.h

@@ -130,6 +130,7 @@ static inline const u32* decomp_soc_detect(void __iomem *dbgu_base)
 	case ARCH_ID_AT91SAM9RL64:
 		return uarts_sam9rl;
 
+	case ARCH_ID_AT91SAM9N12:
 	case ARCH_ID_AT91SAM9X5:
 		return uarts_sam9x5;