MAINTAINERS: co-maintain random.c

random.c is a bit understaffed, and folks want more prompt reviews. I've
got the crypto background and the interest to do these reviews, and have
authored parts of the file already.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

MAINTAINERS

@@ -15979,6 +15979,7 @@ F:	arch/mips/generic/board-ranchu.c
 
 RANDOM NUMBER DRIVER
 M:	"Theodore Ts'o" <tytso@mit.edu>
+M:	Jason A. Donenfeld <Jason@zx2c4.com>
 S:	Maintained
 F:	drivers/char/random.c