[ELF] -M/-Map: fix VMA/LMA/Size columns of symbol assignments when address/size>=2**32

SymbolAssignment::addr stores the location counter. The type should be
uint64_t instead of unsigned. The upper half of the address space is
commonly used by operating system kernels.

Similarly, SymbolAssignment::size should be an uint64_t. A kernel linker
script can move the location counter from 0 to the upper half of the
address space.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D77445