CVE ID:	CVE-2021-47471
Description:	In the Linux kernel, the following vulnerability has been resolved: drm: mxsfb: Fix NULL pointer dereference crash on unload The mxsfb->crtc.funcs may already be NULL when unloading the driver, in which case calling mxsfb_irq_disable() via drm_irq_uninstall() from mxsfb_unload() leads to NULL pointer dereference. Since all we care about is masking the IRQ and mxsfb->base is still valid, just use that to clear and mask the IRQ.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2021-47471 https://git.kernel.org/stable/c/3cfc183052c3dbf8eae57b6c1685dab00ed3db4a https://git.kernel.org/stable/c/3cfc183052c3dbf8eae57b6c1685dab00ed3db4a https://git.kernel.org/stable/c/b0e6db0656ddfd8bb57303c2ef61ee1c1cc694a8 https://git.kernel.org/stable/c/b0e6db0656ddfd8bb57303c2ef61ee1c1cc694a8 https://git.kernel.org/stable/c/f40c2281d2c0674d32ba732fee45222d76495472 https://git.kernel.org/stable/c/f40c2281d2c0674d32ba732fee45222d76495472