[AMDGPU] Fix DynLDS causing crash when LowerLDS is run at fullLTO pipeline (#96038)
Direct mapped dynamic LDS is not lowered in the LowerLDSModule pass.
Hence it is not marked with an absolute symbol. When the LowerLDS pass is
rerun in LTO, compilation fails with an assert "cannot mix abs and non-abs LDVs".
This patch adds an additional check for direct mapped dynLDS to skip the assert.
Fixes SWDEV-454281