x86/early_printk: Set __iomem address space for IO

There are following warnings on unpatched code:

arch/x86/kernel/early_printk.c:198:32: warning: incorrect type in initializer (different address spaces)
arch/x86/kernel/early_printk.c:198:32:    expected void [noderef] <asn:2>*vaddr
arch/x86/kernel/early_printk.c:198:32:    got unsigned int [usertype] *<noident>
arch/x86/kernel/early_printk.c:205:32: warning: incorrect type in initializer (different address spaces)
arch/x86/kernel/early_printk.c:205:32:    expected void [noderef] <asn:2>*vaddr
arch/x86/kernel/early_printk.c:205:32:    got unsigned int [usertype] *<noident>

Annotate it proper.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: http://lkml.kernel.org/r/1444646837-42615-1-git-send-email-andriy.shevchenko@linux.intel.comSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/early_printk.c

@@ -195,14 +195,14 @@ static __init void early_serial_init(char *s)
 #ifdef CONFIG_PCI
 static void mem32_serial_out(unsigned long addr, int offset, int value)
 {
-	u32 *vaddr = (u32 *)addr;
+	u32 __iomem *vaddr = (u32 __iomem *)addr;
 	/* shift implied by pointer type */
 	writel(value, vaddr + offset);
 }
 
 static unsigned int mem32_serial_in(unsigned long addr, int offset)
 {
-	u32 *vaddr = (u32 *)addr;
+	u32 __iomem *vaddr = (u32 __iomem *)addr;
 	/* shift implied by pointer type */
 	return readl(vaddr + offset);
 }