maple_tree: fix comment describing mas_node_count_gfp()

The function description comment for mas_node_count_gfp() mistakingly
refers to the function as mas_node_count().  Change it to refer to the
correct function.

Link: https://lkml.kernel.org/r/20240109223119.162357-1-sidhartha.kumar@oracle.com


Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>