QDMA: libqdma: select timer_container_of() on RHEL backports (9.8+/10.1+)

[amd-vserbu]

Summary

from_timer() was renamed to timer_container_of() upstream in Linux v6.16 (commit 41cb08555c41). The existing guard in qdma_mbox.c keyed solely off LINUX_VERSION_CODE > KERNEL_VERSION(6, 16, 0), which misfires on RHEL-family kernels that backported the rename while keeping an older version string, breaking the build on RHEL/AlmaLinux/Rocky 9.8+ and 10.1+.

Fixes #391

Changes

• Add a QDMA_HAVE_TIMER_CONTAINER_OF feature gate in qdma_compat.h that is defined when either:
  • LINUX_VERSION_CODE >= KERNEL_VERSION(6, 16, 0) (vanilla), or
  • RHEL_RELEASE_CODE indicates 9.8–9.x or 10.1+ (the backported streams: RHEL-115039 for el9, RHEL-114125 for el10).
• The RHEL comparison is nested under #elif defined(RHEL_RELEASE_CODE) so that RHEL_RELEASE_VERSION(...) is never evaluated on non-RHEL kernels (where it is undefined and would otherwise be a preprocessor error).
• qdma_mbox.c now selects the branch via #if defined(QDMA_HAVE_TIMER_CONTAINER_OF).
• Tighten the upstream check from > to >= so a vanilla 6.16.0 kernel is also matched (the rename is present in 6.16).

Testing

Compile-tested make driver KDIR=<tree> against:

• Ubuntu 6.8 kernel (24.04 HWE kernel) and Ubuntu 7.0 kernel (26.04 kernel)
• AlmaLinux 9.8 (kernel-devel-5.14.0-687.12.1.el9_8).