staging: mt7621-mmc: Remove unused macros sdr_{read,write}16

The sdr_{read,write}16 macros are never used and does not provide any
information about the device, so they are removed.
Signed-off-by: Christian Lütke-Stetzkamp <christian@lkamp.de>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-mmc/mt6575_sd.h

@@ -980,10 +980,8 @@ static inline unsigned int uffs(unsigned int x)
 }
 
 #define sdr_read8(reg)            readb(reg)
-#define sdr_read16(reg)           readw(reg)
 #define sdr_read32(reg)           readl(reg)
 #define sdr_write8(reg, val)      writeb(val, reg)
-#define sdr_write16(reg, val)     writew(val, reg)
 #define sdr_write32(reg, val)     writel(val, reg)
 
 static inline void sdr_set_bits(void __iomem *reg, u32 bs)