Focal update: v5.14.21 upstream stable release

    SRU Justification

    Impact:
       The upstream process for stable tree updates is quite similar
       in scope to the Ubuntu SRU process, e.g., each patch has to
       demonstrably fix a bug, and each patch is vetted by upstream
       by originating either directly from a mainline/stable Linux tree or
       a minimally backported form of that patch. The following upstream
       stable patches should be included in the Ubuntu kernel:

       v5.14.21 upstream stable release
       from git://git.kernel.org/

Linux 5.14.21
Revert "ACPI: scan: Release PM resources blocked by unused objects"
thermal: Fix NULL pointer dereferences in of_thermal_ functions
perf/core: Avoid put_page() when GUP fails
PCI: Add MSI masking quirk for Nvidia ION AHCI
PCI/MSI: Deal with devices lying about their MSI mask capability
PCI/MSI: Destroy sysfs before freeing entries
parisc/entry: fix trace test in syscall exit path
Bluetooth: btusb: Add support for TP-Link UB500 Adapter
bootconfig: init: Fix memblock leak in xbc_make_cmdline()
loop: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
fortify: Explicitly disable Clang support
KVM: Fix steal time asm constraints
Revert "drm: fb_helper: fix CONFIG_FB dependency"
Revert "drm: fb_helper: improve CONFIG_FB dependency"