mmc: via-sdmmc: fix return value check of mmc_add_host()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: mmc: via-sdmmc: 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(). Fix this by checking the return value and goto error path which will call mmc_free_host().

References

• https://git.kernel.org/stable/c/076bcd2c93e16b05c10564e299d6e5d26a766d00
• https://git.kernel.org/stable/c/12b8e81b77c05c658efd9cde3585bbd65ae39b59
• https://git.kernel.org/stable/c/95025a8dd0ec015872f6c16473fe04d6264e68ca
• https://git.kernel.org/stable/c/f59ef2a47a228e51322ad76752a55a8917c56e38
• https://git.kernel.org/stable/c/63400da6cd37a9793c19bb6aed7131b58b975a04
• https://git.kernel.org/stable/c/0959cc1685eb19774300d43ef25e318b457b156b
• https://git.kernel.org/stable/c/0ec94795114edc7e24ec71849dce42bfa61dafa3
• https://git.kernel.org/stable/c/ba91b413983a9235792523c6b9f7ba2586c4d75d
• https://git.kernel.org/stable/c/e4e46fb61e3bb4628170810d3f2b996b709b90d9