Add missing <malloc.h> and <string.h> includes.

Change-Id: Ia41756e607663d056e7d2fdd7ecbec7e5841a913
diff --git a/fastbootd/commands/partitions.c b/fastbootd/commands/partitions.c
index 3b27959..953c56a 100644
--- a/fastbootd/commands/partitions.c
+++ b/fastbootd/commands/partitions.c
@@ -42,6 +42,7 @@
 #include <linux/hdreg.h>
 #include <sys/ioctl.h>
 #include <stdlib.h>
+#include <string.h>
 #include <cutils/config_utils.h>
 #include <inttypes.h>