gpio/mpc83xx_spisel_boot.c: include log.h

Fix build failure, it used to get this implicitly through common.h
until f7ae49fc4f (common: Drop log.h from common header).

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/drivers/gpio/mpc83xx_spisel_boot.c b/drivers/gpio/mpc83xx_spisel_boot.c
index c7b0840..54dc437 100644
--- a/drivers/gpio/mpc83xx_spisel_boot.c
+++ b/drivers/gpio/mpc83xx_spisel_boot.c
@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <log.h>
 #include <dm.h>
 #include <mapmem.h>
 #include <asm/gpio.h>