LoongArch: Fix resolution of undefined weak hidden/protected symbols

LoongArch: Fix resolution of undefined weak hidden/protected symbols

An undefined weak hidden/protect symbol should be resolved to runtime
address 0, but we were actually resolving it to link-time address 0.  So
in PIE or DSO the runtime address would be incorrect.

Fix the issue by rewriting pcalau12i to lu12i.w, and pcaddi to addi.w.
The latter does not always work because the immediate field of addi.w is
narrower, report an error in the case the addend is too large.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>