ARM: PL08x: fix a warning

drivers/dma/amba-pl08x.c: In function 'pl08x_start_txd':
drivers/dma/amba-pl08x.c:205: warning: dereferencing 'void *' pointer

We never dereference llis_va aside from assigning it to a struct
pl08x_lli pointer or calculating the address of array element 0.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

include/linux/amba/pl08x.h

@@ -118,7 +118,7 @@ struct pl08x_txd {
 	dma_addr_t dst_addr;
 	size_t len;
 	dma_addr_t llis_bus;
-	void *llis_va;
+	struct pl08x_lli *llis_va;
 	bool active;
 	/* Default cctl value for LLIs */
 	u32 cctl;