net/mlx5: Fix error handling in irq_pool_request_irq

net/mlx5: Fix error handling in irq_pool_request_irq

In case mlx5_irq_alloc fails, the previously allocated index remains
in the XArray, which could lead to inconsistencies.

Fix it by adding error handling that erases the allocated index
from the XArray if mlx5_irq_alloc returns an error.

Fixes: c36326d38d93 ("net/mlx5: Round-Robin EQs over IRQs")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Maher Sanalla <msanalla@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Link: https://patch.msgid.link/20240730061638.1831002-3-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>