csky: pgtable: Fixup update_mmu_cache for abiv2

The csky instruction cache is VIPT, and it needs an origin virtual
address to invalidate the virtual address index entries of cache ways.
The current implementation uses a temporary mapping mechanism -
kmap_atomic, which returns a fake virtual address for invalidation. The
original virtual address cache line may still be in the icache.

So correct icache invalidation arguments by origin virtual address
instead of kmap_atomic returned value.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>