static int getLo12(int target) {
		return (target & 0x00000fff);
	}
get the lower 12 bits of a 32 bit target.  These will typically be added - not or'ed - to
a register holding the higher 20 bits.
@param target a 32 bit offset
@return the lower 12 bits of target
Ghidra/Processors/RISCV/src/main/java/ghidra/app/util/bin/format/elf/relocation/RISCV_ElfRelocationHandler.java