Module build fails on RHEL8.6 as kmap_types.h is removed from kernel-devel.

Issue

• Module build fails on RHEL8.6 as kmap_types.h is removed from kernel-devel.

# /etc/init.d/beegfs-client rebuild
- BeeGFS module autobuild
Building beegfs client module
feature detection gives: -DKERNEL_HAS_SCHED_SIG_H -DKERNEL_HAS_STATX -DKERNEL_HAS_KREF_READ -DKERNEL_HAS_FILE_DENTRY -DKERNEL_HAS_SUPER_SETUP_BDI_NAME -DKERNEL_HAS_KERNEL_READ -DKERNEL_HAS_SKWQ_HAS_SLEEPER -DKERNEL_WAKE_UP_SYNC_KEY_HAS_3_ARGUMENTS -DKERNEL_HAS_GET_FS -DKERNEL_HAS_IOV_ITER_KVEC_NO_TYPE_FLAG_IN_DIRECTION -DKERNEL_HAS_PRINT_STACK_TRACE -DKERNEL_HAS_SOCKPTR_T -DKERNEL_HAS_TIME64 -DKERNEL_HAS_KTIME_GET_TS64 -DKERNEL_HAS_KTIME_GET_REAL_TS64 -DKERNEL_HAS_KTIME_GET_COARSE_REAL_TS64
In file included from /opt/beegfs/src/client/client_module_7/build/../source/common/toolkit/Serialization.h:27,
                 from /opt/beegfs/src/client/client_module_7/build/../source/common/net/message/control/../NetMessage.h:6,
                 from /opt/beegfs/src/client/client_module_7/build/../source/common/net/message/control/../SimpleStringMsg.h:4,
                 from /opt/beegfs/src/client/client_module_7/build/../source/common/net/message/control/AckMsgEx.h:4,
                 from /opt/beegfs/src/client/client_module_7/build/../source/net/message/NetMessageFactory.c:2:
/opt/beegfs/src/client/client_module_7/build/../source/os/OsCompat.h:11:10: fatal error: asm/kmap_types.h: No such file or directory
 #include <asm/kmap_types.h>
          ^~~~~~~~~~~~~~~~~~