rt2x00: make csr_cache and csr_addr an union

The csr_cache and csr_addr pointers are both the same size
and they are never used both by the same driver. This makes
them a nice candidate for an union.
We could merge into 1 pointer, but that would either upset sparse,
or require a lot of __force casts.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index f6ec9fe..9098532 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -707,11 +707,13 @@
 
 	/*
 	 * Register pointers
-	 * csr_addr: Base register address. (PCI)
-	 * csr_cache: CSR cache for usb_control_msg. (USB)
+	 * csr.base: CSR base register address. (PCI)
+	 * csr.cache: CSR cache for usb_control_msg. (USB)
 	 */
-	void __iomem *csr_addr;
-	void *csr_cache;
+	union csr {
+		void __iomem *base;
+		void *cache;
+	} csr;
 
 	/*
 	 * Mutex to protect register accesses on USB devices.