i2c-i801: Include <linux/slab.h>

Commit 5a0e3ad6 added direct inclusion
of <linux/slab.h> to those source files that appeared to need it, but
somehow missed this.  On most architectures <linux/slab.h> is still
indirectly included, but there are exceptions such as alpha.
Signed-off-by: NBen Hutchings <ben@decadent.org.uk>
Signed-off-by: NJean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-i801.c

@@ -72,6 +72,7 @@
 #include <linux/acpi.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
+#include <linux/slab.h>
 
 /* I801 SMBus address offsets */
 #define SMBHSTSTS(p)	(0 + (p)->smba)