random32: Re-enable KCSAN instrumentation

Re-enable KCSAN instrumentation, now that KCSAN no longer relies on code
in lib/random32.c.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

lib/Makefile

@@ -27,9 +27,6 @@ KASAN_SANITIZE_string.o := n
 CFLAGS_string.o += -fno-stack-protector
 endif
 
-# Used by KCSAN while enabled, avoid recursion.
-KCSAN_SANITIZE_random32.o := n
-
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o timerqueue.o xarray.o \
 	 idr.o extable.o sha1.o irq_regs.o argv_split.o \