clk: sirf: Silence sparse warnings

These are __iomem pointers. Mark them appropriately so we don't
get sparse errors like

drivers/clk/sirf/clk-common.c:60:16: warning: incorrect type in argument 1 (different address spaces)
drivers/clk/sirf/clk-common.c:60:16:    expected void const volatile [noderef] <asn:2>*addr
drivers/clk/sirf/clk-common.c:60:16:    got void *

Cc: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/sirf/clk-common.c

@@ -10,8 +10,8 @@
 #define KHZ     1000
 #define MHZ     (KHZ * KHZ)
 
-static void *sirfsoc_clk_vbase;
-static void *sirfsoc_rsc_vbase;
+static void __iomem *sirfsoc_clk_vbase;
+static void __iomem *sirfsoc_rsc_vbase;
 static struct clk_onecell_data clk_data;
 
 /*