RDMA/hns: Remove the struct member 'bond_grp' from hns_roce_dev

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6Z4E9



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Currently, bond_grp is attached to only one hr_dev corresponding to a
slave in RoCE bonding, which is called main_hr_dev in the driver. When
a non-main_hr_dev try to obtain its bond_grp, the driver has to find
the main_hr_dev, and then obtain the bond_grp, which leads to a
complicated code.

Applying this patch, bond_grp is removed from struct hns_roce_dev. hr_dev
can obtain bond_grp by XArray, where die_info and bond_grp are stored
according to bus number. With this change, hr_dev can get its bond_grp
directly without depending on main_hr_dev, and the code logic can be
simplified.

Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>