* Fix IPEX attn_drop
* IPEX SDPA 4GB fix
Alchemist GPUs lack the 64 bit emulation needed for >4GB in this case. Attention slicing workaround copied from https://github.com/vladmandic/automatic/blob/master/modules/intel/ipex/attention.py
* Do 4GB fix only when necessary
~20% performance boost to not use the 4GB fix when not necessary
* Move attention.py inside utils
* Better 4GB estimation
* Remove unnecessary warning
