[ELF][PPC][X86] Use [-2**(n-1), 2**n) to check overflows for R_PPC_ADDR16,...

[ELF][PPC][X86] Use [-2**(n-1), 2**n) to check overflows for R_PPC_ADDR16, R_PPC64_ADDR{16,32}, R_X86_64_{8,16}

Similar to R_AARCH64_ABS32, R_PPC64_ADDR32 can represent either a signed
value or unsigned value, thus we should use `[-2**(n-1), 2**n)` instead of
`[-2**(n-1), 2**(n-1))` to check overflows.

The issue manifests as a bogus linker error when linking the powerpc64le Linux kernel.
The new behavior is compatible with ld.bfd's complain_overflow_bitfield.

The upper bound of the error message is not correct. Fix it as well.

The changes to R_PPC_ADDR16, R_PPC64_ADDR16, R_X86_64_8 and R_X86_64_16 are similar.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63690

llvm-svn: 364164