i2c: cpm: Fix build break due to incompatible pointer types

Since commit ea8daa7b ("kbuild: Add option to turn incompatible
pointer check into error"), assignments from an incompatible pointer
types have become a hard error, eg:

  drivers/i2c/busses/i2c-cpm.c:545:91: error: passing argument 3 of
  'dma_alloc_coherent' from incompatible pointer type

Fix the build break by converting txdma & rxdma to dma_addr_t.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Fixes: ea8daa7b

drivers/i2c/busses/i2c-cpm.c

@@ -116,8 +116,8 @@ struct cpm_i2c {
 	cbd_t __iomem *rbase;
 	u_char *txbuf[CPM_MAXBD];
 	u_char *rxbuf[CPM_MAXBD];
-	u32 txdma[CPM_MAXBD];
-	u32 rxdma[CPM_MAXBD];
+	dma_addr_t txdma[CPM_MAXBD];
+	dma_addr_t rxdma[CPM_MAXBD];
 };
 
 static irqreturn_t cpm_i2c_interrupt(int irq, void *dev_id)