maple_tree: mas_anode_descend() clang-analyzer cleanup

clang-analyzer reported some Dead Stores in mas_anode_descend().  Upon
inspection, there were a few clean ups that would make the code cleaner:

The count variable was set from the mt_slots array and then updated but
never used again.  Just use the array reference directly.

Also stop updating the type since it isn't used after the update.

Stop setting the gaps pointer to NULL at the start since it is always
set before the loop begins.

Link: https://lkml.kernel.org/r/20221026151413.4032730-1-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/maple_tree.c

@@ -4968,8 +4968,9 @@ static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size)
 {
 	enum maple_type type = mte_node_type(mas->node);
 	unsigned long pivot, min, gap = 0;
-	unsigned char count, offset;
-	unsigned long *gaps = NULL, *pivots = ma_pivots(mas_mn(mas), type);
+	unsigned char offset;
+	unsigned long *gaps;
+	unsigned long *pivots = ma_pivots(mas_mn(mas), type);
 	void __rcu **slots = ma_slots(mas_mn(mas), type);
 	bool found = false;
 
@@ -4980,9 +4981,8 @@ static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size)
 
 	gaps = ma_gaps(mte_to_node(mas->node), type);
 	offset = mas->offset;
-	count = mt_slots[type];
 	min = mas_safe_min(mas, pivots, offset);
-	for (; offset < count; offset++) {
+	for (; offset < mt_slots[type]; offset++) {
 		pivot = mas_safe_pivot(mas, pivots, offset, type);
 		if (offset && !pivot)
 			break;
@@ -5008,8 +5008,6 @@ static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size)
 				mas->min = min;
 				mas->max = pivot;
 				offset = 0;
-				type = mte_node_type(mas->node);
-				count = mt_slots[type];
 				break;
 			}
 		}