spi: bcm-qspi: return error if neither hif_mspi nor mspi is available

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: spi: bcm-qspi: return error if neither hif_mspi nor mspi is available If neither a "hif_mspi" nor "mspi" resource is present, the driver will just early exit in probe but still return success. Apart from not doing anything meaningful, this would then also lead to a null pointer access on removal, as platform_get_drvdata() would return NULL, which it would then try to dereference when trying to unregister the spi master. Fix this by unconditionally calling devm_ioremap_resource(), as it can handle a NULL res and will then return a viable ERR_PTR() if we get one. The "return 0;" was previously a "goto qspi_resource_err;" where then ret was returned, but since ret was still initialized to 0 at this place this was a valid conversion in 63c5395bb7a9 ("spi: bcm-qspi: Fix use-after-free on unbind"). The issue was not introduced by this commit, only made more obvious.

References

• https://git.kernel.org/stable/c/a91c34357afcfaa5307e254f22a8452550a07b34
• https://git.kernel.org/stable/c/d20db3c58a7f9361e370a7850ceb60dbdf62eea3
• https://git.kernel.org/stable/c/398e6a015877d44327f754aeb48ff3354945c78c
• https://git.kernel.org/stable/c/32b9c8f7892c19f7f5c9fed5fb410b9fd5990bb6
• https://git.kernel.org/stable/c/217b6ea8cf7b819477bca597a6ae2d43d38ba283
• https://git.kernel.org/stable/c/d3dcdb43c872a3b967345144151a2c9bb9124c9b
• https://git.kernel.org/stable/c/22ae32d80ef590d12a2364e4621f90f7c58445c7
• https://git.kernel.org/stable/c/7c1f23ad34fcdace50275a6aa1e1969b41c6233f