Kernel crashes when accessing port_speed sysfs file.  The issue happens on
a CNA when the local array was accessed beyond bounds. Fix this by changing
the lookup.

BUG: unable to handle kernel paging request at 0000000000004000
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI
CPU: 15 PID: 455213 Comm: sosreport Kdump: loaded Not tainted
4.18.0-305.7.1.el8_4.x86_64 #1
RIP: 0010:string_nocheck+0x12/0x70
Code: 00 00 4c 89 e2 be 20 00 00 00 48 89 ef e8 86 9a 00 00 4c 01
e3 eb 81 90 49 89 f2 48 89 ce 48 89 f8 48 c1 fe 30 66 85 f6 74 4f <44> 0f b6 0a
45 84 c9 74 46 83 ee 01 41 b8 01 00 00 00 48 8d 7c 37
RSP: 0018:ffffb5141c1afcf0 EFLAGS: 00010286
RAX: ffff8bf4009f8000 RBX: ffff8bf4009f9000 RCX: ffff0a00ffffff04
RDX: 0000000000004000 RSI: ffffffffffffffff RDI: ffff8bf4009f8000
RBP: 0000000000004000 R08: 0000000000000001 R09: ffffb5141c1afb84
R10: ffff8bf4009f9000 R11: ffffb5141c1afce6 R12: ffff0a00ffffff04
R13: ffffffffc08e21aa R14: 0000000000001000 R15: ffffffffc08e21aa
FS:  00007fc4ebfff700(0000) GS:ffff8c717f7c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000004000 CR3: 000000edfdee6006 CR4: 00000000001706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  string+0x40/0x50
  vsnprintf+0x33c/0x520
  scnprintf+0x4d/0x90
  qla2x00_port_speed_show+0xb5/0x100 [qla2xxx]
  dev_attr_show+0x1c/0x40
  sysfs_kf_seq_show+0x9b/0x100
  seq_read+0x153/0x410
  vfs_read+0x91/0x140
  ksys_read+0x4f/0xb0
  do_syscall_64+0x5b/0x1a0
  entry_SYSCALL_64_after_hwframe+0x65/0xca

Link: https://lore.kernel.org/r/20210908164622.19240-7-njavali@marvell.com
Fixes: 4910b524 ("scsi: qla2xxx: Add support for setting port speed")
Cc: stable@vger.kernel.org
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>