RISC-V: Fixed missed GOT relocation against a symbol that has a defined value

RISC-V: Fixed missed GOT relocation against a symbol that has a defined value

SImilar to aarch64, commit eac4eb8ecb26

There are two problems when GOT relocation against a symbol that has a defined
value,
1. Pesudo la with pic and pseudo lga lost the relocations.
2. %got_pcrel_hi generates R_RISCV_GOT_HI20 with addend, which is wrong since
   commit 50331d64f108.

The solution is to use deferred_expression for GOT relocation.  Maybe other
relocations also have same problem and need the deferred_expression, but we can
add in the future patches.