staging/lustre: Use roundup_pow_of_two() in LNetEQAlloc()

Use roundup_pow_of_two() and drop the private cfs_power2_roundup()
implementation.

Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>