Follow-up to #141333. Relocation generation called both addReloc and
applyFixup, with the default addReloc invoking shouldForceRelocation,
resulting in three virtual calls. This approach was also inflexible, as
targets needing additional data required extending
`shouldForceRelocation` (see #73721, resolved by #141311).

This change integrates relocation handling into applyFixup, eliminating
two virtual calls. The prior default addReloc is renamed to
maybeAddReloc. Targets overriding addReloc now call their customized
addReloc implementation.

When targeting GFX950, disassembly of v_permlane16_swap_b32 and
v_permlane32_swap_b32 instructions produces errors when they use certain
vdst operand values, e.g., v_permlane16_swap_b32 v218, v219. This patch
fixes this problem.

Putting the complex condition in a variable does not help readability.
It is simpler to use separate `if`s.

This can help to identify if there is potential hazards.

Co-authored-by: Byrnes, Jeffrey <Jeffrey.Byrnes@amd.com>

MC layer only.

These two instructions are supported by gfx1250. We define the
instructions and implement the corresponding intrinsic and builtin.

Co-authored-by: Stanislav Mekhanoshin <Stanislav.Mekhanoshin@amd.com>

Val is already of uint64_t.