maple_tree: fix comment typo on ma_flag of allocation tree

The maple tree flag of allocation tree is MT_FLAGS_ALLOC_RANGE.

Just correct it.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Wei Yang <[e-mail]>
Reviewed-by: Liam R. Howlett <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

include/linux/maple_tree.h

···
  * bit in the node type.  This is possible by using bit 1 to indicate if bit 2
  * is part of the type or the slot.
  *
- * Once the type is decided, the decision of an allocation range type or a range
- * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE
- * flag.
+ * Once the type is decided, the decision of an allocation range type or a
+ * range type is done by examining the immutable tree flag for the
+ * MT_FLAGS_ALLOC_RANGE flag.
  *
  *  Node types:
  *   0x??1 = Root