Feature/revpi 1833/cleanup

[linosanfilippo-kunbus]

• remove fc3aea683927df3eb531acdde56eb6a98eddb484 ("Revert "[HACK] Compact: Disable MAX31913 status"")
• remove ff433a175f2288a99936729e459f30e2df10b8c5 ("[HACK] Compact: Disable MAX31913 status")
• remove 66eb9fd3a11d7cd4ae25821ea0f547a662d256a1 ("Gate: Set TC_PRIO_REALTIME only on kernel < 4.20")
• remove 88b61ddb2a2510cb399e6275ab0137c5ad3b7f6a ("fixup! Gate: Set TC_PRIO_REALTIME only on kernel < 4.20")
• remove 3e69a79628e91526dd80096dcf962e60fb21c22c ("[HACK] the access_ok macro has changed with 5.0.0")
• move c47048399e9c31bcfeb1b264e5ad4546a5cedc6f ("piControl: use correct function to exchange data with userspace")
• add 35a76e0e95839de2f2a9b380f02a114680de631d "(HEAD -> feature/REVPI-1833/cleanup, origin/feature/REVPI-1833/cleanup) piControl: compact: Replace smp_read_barrier_depends() with smp_rmb()")