xtensa: nommu: provide MAP_UNINITIALIZED definition

Add MAP_UNINITIALIZED to xtensa version of mman.h to keep mm/nommu.c
happy.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/include/uapi/asm/mman.h

@@ -55,6 +55,12 @@
 #define MAP_NONBLOCK	0x20000		/* do not block on IO */
 #define MAP_STACK	0x40000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x80000		/* create a huge page mapping */
+#ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
+# define MAP_UNINITIALIZED 0x4000000	/* For anonymous mmap, memory could be
+					 * uninitialized */
+#else
+# define MAP_UNINITIALIZED 0x0		/* Don't support this flag */
+#endif
 
 /*
  * Flags for msync