The standard page wasn't adapted for LoongArch since day one. Remove
the references to IA32 and AMD64, and state there's no LoongArch
specific part of LSB. Also we cannot satisify some (really
unreasonable) requirements on symbol versions with Glibc on LoongArch.
By the way drop libutil.so.1 from Glibc contents as it does not exist on
LoongArch.