locking/rwsem: drop redundant semicolon of down_write_nest_lock

Otherwise, braces are needed when using it.

Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220114083742.6219-1-guchun.chen@amd.com


Signed-off-by: Christian König <christian.koenig@amd.com>