maple_tree: avoid duplicate variable init in mast_spanning_rebalance()

The local variables r_tmp and l_tmp in mast_spanning_rebalance() are
already initialized at its declaration; there is no need to assign the
value again.

Remove the duplicate initialization of {r,l}_tmp.  No functional change. 
Due to common compiler optimizations, also no change to object code.

This issue was identified with clang-analyzer's dead stores analysis.

Link: https://lkml.kernel.org/r/20240122102000.29558-1-lukas.bulwahn@gmail.com


Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>