[NFC][libclc][libspirv] Move get_num_sub_groups.cl/get_sub_group_size.cl to generic (#16620)

Implementation is the same for ptx and amdgcn.

Author: wenju-he

libclc/libspirv/lib/amdgcn-amdhsa/SOURCES

@@ -64,10 +64,8 @@ workitem/get_global_size.cl
 workitem/get_local_size.cl
 workitem/get_num_groups.cl
 workitem/get_max_sub_group_size.cl
-workitem/get_num_sub_groups.cl
 workitem/get_sub_group_id.cl
 workitem/get_sub_group_local_id.cl
-workitem/get_sub_group_size.cl
 misc/sub_group_shuffle.cl
 async/wait_group_events.cl
 assert/__assert_fail.ll

libclc/libspirv/lib/generic/SOURCES

@@ -206,3 +206,5 @@ shared/vload.cl
 shared/vstore.cl
 workitem/get_global_id.cl
 workitem/get_global_size.cl
+workitem/get_num_sub_groups.cl
+workitem/get_sub_group_size.cl

libclc/libspirv/lib/amdgcn-amdhsa/workitem/get_num_sub_groups.cl renamed to libclc/libspirv/lib/generic/workitem/get_num_sub_groups.cl

@@ -84,10 +84,8 @@ workitem/get_local_id.cl
 workitem/get_local_size.cl
 workitem/get_max_sub_group_size.cl
 workitem/get_num_groups.cl
-workitem/get_num_sub_groups.cl
 workitem/get_sub_group_id.cl
 workitem/get_sub_group_local_id.cl
-workitem/get_sub_group_size.cl
 images/image_helpers.ll
 images/image.cl
 group/collectives_helpers.ll