Fix paged attention for vision models on multiple devices

[cdoko]

The DeviceMapper was set to None for vision models before, now it's being passed properly. Tested working on Phi3V.

[github-actions]

Code Metrics Report

  ===============================================================================
 Language            Files        Lines         Code     Comments       Blanks
===============================================================================
 C Header                2           35           28            0            7
 Dockerfile              1           41           22           10            9
 JSON                   12          105          104            0            1
 Python                 66         2801         2425           72          304
 Shell                   1           57           22           18           17
 Plain Text              3         3723            0         2413         1310
 TOML                   18          619          550            2           67
 YAML                    2           21           19            2            0
-------------------------------------------------------------------------------
 Jupyter Notebooks       4            0            0            0            0
 |- Markdown             2           77           32           31           14
 |- Python               2          205          178            1           26
 (Total)                            282          210           32           40
-------------------------------------------------------------------------------
 Markdown               44         3491            0         2650          841
 |- BASH                 6          103          100            0            3
 |- JSON                 1           12           12            0            0
 |- Python               7          121          109            0           12
 |- Rust                13          440          373            0           67
 |- TOML                 2           75           63            0           12
 (Total)                           4242          657         2650          935
-------------------------------------------------------------------------------
 Rust                  301        96256        86291         1958         8007
 |- Markdown           145         1672           25         1524          123
 (Total)                          97928        86316         3482         8130
===============================================================================
 Total                 454       107149        89461         7125        10563
===============================================================================
  

[EricLBuehler]

Thank you!