vboot-utils: MTD_CHAR_MAJOR definition

This definition missing from <linux/major.h> for kernels <= 3.13.

Signed-off-by: Alex Suykov <alex.suykov@gmail.com>

--- a/cgpt/cgpt_wrapper.c

+++ b/cgpt/cgpt_wrapper.c

@@ -25,6 +25,10 @@

 #include "cgpt_nor.h"

 #include "cryptolib.h"

+#ifndef MTD_CHAR_MAJOR

+#define MTD_CHAR_MAJOR 90

+#endif

+

 // Check if cmdline |argv| has "-D". "-D" signifies that GPT structs are stored

 // off device, and hence we should not wrap around cgpt.

 static bool has_dash_D(int argc, const char *const argv[]) {