Linker relaxation may change code size. We need to fix up the alignment by inserting Nops and R_RISCV_ALIGN relocation type. So then linker could satisfy the alignment by removing Nops.
To do this:
1. Add insertNopBytesForAlignDirectiveInTextSection target hook to calculate the Nops we need to insert.
2. Add insertFixupForAlignDirectiveInTextSection target hook to insert the fixup type.