6.15: Build error with CONFIG_BCACHEFS_FS

When compiling with CONFIG_BCACHEFS_FS I get the following error:

  CC [M]  fs/bcachefs/io_write.o
fs/bcachefs/io_write.c: In function ‘__wp_update_state’:
fs/bcachefs/io_write.c:628:32: error: ‘struct task_struct’ has no member named ‘se’
  628 |                 u64 runtime = p->se.sum_exec_runtime +
      |                                ^~
fs/bcachefs/io_write.c:629:33: error: ‘struct task_struct’ has no member named ‘se’
  629 |                         (now - p->se.exec_start);
      |                                 ^~

Seems to be caused by upstream commit 999cc1bb