Describe CVE-2021-47051.
What is CVE-2021-47051?
In the Linux kernel, the following vulnerability has been resolved:

spi: fsl-lpspi: Fix PM reference leak in lpspi_prepare_xfer_hardware()

pm_runtime_get_sync will increment pm usage counter even it failed.
Forgetting to putting operation will result in reference leak here.
Fix it by replacing it with pm_runtime_resume_and_get to keep usage
counter balanced..