mmc: Allow 2 byte requests in 4-bit mode for tmio_mmc

Adjust the tmio_mmc block size check to accept 2-byte requests in 4-bit
mode if the hardware supports it.

Tested with the SDHI hardware block included in sh7724.

Signed-off-by: Yusuke Goda <yusuke.goda.sx@renesas.com>
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Acked-by: Magnus Damm <damm@opensource.se>
Tested-by: Arnd Hannemann <arnd@arndnet.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/mfd/tmio.h b/include/linux/mfd/tmio.h
index 24c43bb..085f041 100644
--- a/include/linux/mfd/tmio.h
+++ b/include/linux/mfd/tmio.h
@@ -52,6 +52,11 @@
 
 /* tmio MMC platform flags */
 #define TMIO_MMC_WRPROTECT_DISABLE	(1 << 0)
+/*
+ * Some controllers can support a 2-byte block size when the bus width
+ * is configured in 4-bit mode.
+ */
+#define TMIO_MMC_BLKSZ_2BYTES		(1 << 1)
 
 int tmio_core_mmc_enable(void __iomem *cnf, int shift, unsigned long base);
 int tmio_core_mmc_resume(void __iomem *cnf, int shift, unsigned long base);