Update to 5.11 to match Linux kernel 5.11

Changelog

• fix device path canonicalization for device mapper devices
• receive: remove workaround for setting capabilities, all stable kernels have been patched
• receive: fix duplicate mount path detection
• rescue: new subcommand create-control-device
• device stats: minor fix for plain text format output
• build: detect if e2fsprogs support 64bit timestamps
• build: drop libmount, required functionality has been reimplemented
• mkfs: warn when raid56 is used
• balance convert: warn when raid56 is used
• other
  • new and updated tests
  • documentation updates
  • seeding device
  • raid56 status