i2c: rcar: fix mask value of prohibited bit

According to documentation, Bit 7 of ICMSR is unused and 0 should be
written to it. Fix the mask accordingly.
Signed-off-by: NHiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
[wsa: edited commit message]
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-rcar.c

@@ -102,8 +102,8 @@
 #define RCAR_IRQ_RECV	(MNR | MAL | MST | MAT | MDR)
 #define RCAR_IRQ_STOP	(MST)
 
-#define RCAR_IRQ_ACK_SEND	(~(MAT | MDE) & 0xFF)
-#define RCAR_IRQ_ACK_RECV	(~(MAT | MDR) & 0xFF)
+#define RCAR_IRQ_ACK_SEND	(~(MAT | MDE) & 0x7F)
+#define RCAR_IRQ_ACK_RECV	(~(MAT | MDR) & 0x7F)
 
 #define ID_LAST_MSG	(1 << 0)
 #define ID_FIRST_MSG	(1 << 1)