mmc: hsq: Fix use-after-free in retry work

In the Linux kernel, the following vulnerability has been resolved: mmc: hsq: Fix use-after-free in retry work mmc_hsq_pump_requests() queues retry_work when request_atomic() returns -EBUSY; today sdhci-sprd is the only consumer that implements request_atomic(). The work is embedded in a devm-allocated mmc_hsq, but is never cancelled during driver removal. Work still pending at unbind can therefore run after the devm allocation has been released and dereference hsq->mmc and hsq->mrq. Use devm_work_autocancel() to cancel and drain retry_work before the devm allocation is released. By the time devres cleanup begins, mmc_remove_host() has already stopped the host, so no new requests can arm the work. This issue was found by an in-house static analysis tool.