ac/surface/tests: Remove duplicate variable block_size_bits
What does this MR do and why?
ac/surface/tests: Remove duplicate variable block_size_bits
Fix defect reported by Coverity Scan.
Evaluation order violation (EVALUATION_ORDER)
write_write_typo: In block_size_bits = block_size_bits = ((surf.u.gfx9.swizzle_mode >= ADDR_SW_256KB_Z_X) ? 18 : 16),
block_size_bits is written twice with the same value.
Fixes: 44eaf50a34b ("ac/surface/tests: cosmetic changes")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>