scsi: hisi_sas: Correct the number of global debugfs registers

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8IL6H


CVE: NA

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In function debugfs_debugfs_snapshot_global_reg_v3_hw() it uses
debugfs_axi_reg.count (which is the number of axi debugfs registers) to
acquire the number of global debugfs registers.

Use debugfs_global_reg.count to acquire the number of global debugfs
registers instead.

Fixes: 623a4b6d ("scsi: hisi_sas: Move debugfs code to v3 hw driver")
Signed-off-by: Yihang Li <liyihang9@huawei.com>
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: xiabing <xiabing12@h-partners.com>