[QNNPACK, Sparsity] Code refactoring to allow for more generic block (#51118)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51118
sparsity
Modify BCSR to pack generic block sparsity pattern.
Modify rest of the code to accommodate the change.
This is in preperation to support 8x1 sparsity.
Test Plan:
q8gemm-sparse-test
Imported from OSS
Reviewed By: AshkanAliabadi
Differential Revision: D26077767
fbshipit-source-id: 7179975b07a1cb76ef26896701d782fb04638743
