x86/eisa: Add missing include

The seperation of the EISA init missed to include linux/io.h which breaks
the build with some special configurations.

Reported-by: Ingo Molnar <mingo@kernel.org>
Fixes: f7eaf6e00fd5 ("x86/boot: Move EISA setup to a separate file")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/eisa.c

@@ -5,6 +5,7 @@
  */
 #include <linux/ioport.h>
 #include <linux/eisa.h>
+#include <linux/io.h>
 
 static __init int eisa_bus_probe(void)
 {