mmc: atmel-mci: fix return value check of mmc_add_host()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: mmc: atmel-mci: fix return value check of mmc_add_host() mmc_add_host() may return error, if we ignore its return value, it will lead two issues: 1. The memory that allocated in mmc_alloc_host() is leaked. 2. In the remove() path, mmc_remove_host() will be called to delete device, but it's not added yet, it will lead a kernel crash because of null-ptr-deref in device_del(). So fix this by checking the return value and calling mmc_free_host() in the error path.

References

• https://git.kernel.org/stable/c/99a6cdfa2cf05028b52f6d8ee85ccc5f8b71b4a2
• https://git.kernel.org/stable/c/6bb26abb92f25e582a0976091a10b539fe3796db
• https://git.kernel.org/stable/c/00ac0f5f95920f003cd6ece53cdc759549b69118
• https://git.kernel.org/stable/c/1925472dec31ec061d57412b3a65a056ea24f340
• https://git.kernel.org/stable/c/cc8bb436f3c842a86b9082d97933582120d180e2
• https://git.kernel.org/stable/c/85946ceb0fac20ab39cdb85333086daf0291a553
• https://git.kernel.org/stable/c/9e6e8c43726673ca2abcaac87640b9215fd72f4c