[BUG] discard_granularity is 0 on rk3399-gru-kevin

[Vicente Bergas]

Hi,
since recently the rk3399-gru-kevin is reporting the trace below.
The issue has been uncovered by
  b35fd7422c2f8e04496f5a770bd4e1a205414b3f
  block: check queue's limits.discard_granularity in 
__blkdev_issue_discard()

Regards,
 Vicente.

WARNING: CPU: 0 PID: 135 at __blkdev_issue_discard+0x200/0x294
CPU: 0 PID: 135 Comm: f2fs_discard-17 Not tainted 5.9.0-rc6 #1
Hardware name: Google Kevin (DT)
pstate: 00000005 (nzcv daif -PAN -UAO BTYPE=--)
pc : __blkdev_issue_discard+0x200/0x294
lr : __blkdev_issue_discard+0x54/0x294
sp : ffff800011dd3b10
x29: ffff800011dd3b10 x28: 0000000000000000 
x27: ffff800011dd3cc4 x26: ffff800011dd3e18 
x25: 000000000004e69b x24: 0000000000000c40 
x23: ffff0000f1deaaf0 x22: ffff0000f2849200 
x21: 00000000002734d8 x20: 0000000000000008 
x19: 0000000000000000 x18: 0000000000000000 
x17: 0000000000000000 x16: 0000000000000000 
x15: 0000000000000000 x14: 0000000000000394 
x13: 0000000000000000 x12: 0000000000000000 
x11: 0000000000000000 x10: 00000000000008b0 
x9 : ffff800011dd3cb0 x8 : 000000000004e69b 
x7 : 0000000000000000 x6 : ffff0000f1926400 
x5 : ffff0000f1940800 x4 : 0000000000000000 
x3 : 0000000000000c40 x2 : 0000000000000008 
x1 : 00000000002734d8 x0 : 0000000000000000 
Call trace:
 __blkdev_issue_discard+0x200/0x294
 __submit_discard_cmd+0x128/0x374
 __issue_discard_cmd_orderly+0x188/0x244
 __issue_discard_cmd+0x2e8/0x33c
 issue_discard_thread+0xe8/0x2f0
 kthread+0x11c/0x120
 ret_from_fork+0x10/0x1c
---[ end trace e4c8023d33dfe77a ]---
mmcblk1p2: Error: discard_granularity is 0.
mmcblk1p2: Error: discard_granularity is 0.
<last message repeated multiple times>