drm/i915/selftests: fix smatch warning in igt_check_blocks

The block here can't be NULL, especially since we already dereferenced
it earlier, so remove the redundant check.

igt_check_blocks() warn: variable dereferenced before check 'block' (see line 126)
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210702104642.1189978-1-matthew.auld@intel.com

drivers/gpu/drm/i915/selftests/i915_buddy.c

@@ -166,10 +166,8 @@ static int igt_check_blocks(struct i915_buddy_mm *mm,
 		igt_dump_block(mm, prev);
 	}
 
-	if (block) {
-		pr_err("bad block, dump:\n");
-		igt_dump_block(mm, block);
-	}
+	pr_err("bad block, dump:\n");
+	igt_dump_block(mm, block);
 
 	return err;
 }