staging: gpib: Agilent usb code cleanup

staging: gpib: Agilent usb code cleanup

Remove useless #ifdef RESET_USB_CONFIG code.

Change kalloc / memset to kzalloc

The attach function was not freeing the private data on error
returns. Separate the releasing of urbs and private data and
add a common error exit for attach failure.

Set the board private data pointer to NULL after freeing
the private data.

Reduce console spam by emitting only one attach message.

Change last pr_err in attach to dev_err

Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Link: https://lore.kernel.org/r/20250118145046.12181-3-dpenkler@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>