ice: cleanup Rx queue context programming functions

ice: cleanup Rx queue context programming functions

The ice_copy_rxq_ctx_to_hw() and ice_write_rxq_ctx() functions perform some
defensive checks which are typically frowned upon by kernel style
guidelines.

In particular, NULL checks on buffers which point to the stack are
discouraged, especially when the functions are static and only called once.
Checks of this sort only serve to hide potential programming error, as we
will not produce the normal crash dump on a NULL access.

In addition, ice_copy_rxq_ctx_to_hw() cannot fail in another way, so could
be made void.

Future support for VF Live Migration will need to introduce an inverse
function for reading Rx queue context from HW registers to unpack it, as
well as functions to pack and unpack Tx queue context from HW.

Rather than copying these style issues into the new functions, lets first
cleanup the existing code.

For the ice_copy_rxq_ctx_to_hw() function:

 * Move the Rx queue index check out of this function.
 * Convert the function to a void return.
 * Use a simple int variable instead of a u8 for the for loop index, and
   initialize it inside the for loop.
 * Update the function description to better align with kernel doc style.

For the ice_write_rxq_ctx() function:

 * Move the Rx queue index check into this function.
 * Update the function description with a Returns: to align with kernel doc
   style.

These changes align the existing write functions to current kernel
style, and will align with the style of the new functions added when we
implement live migration in a future series.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241210-packing-pack-fields-and-ice-implementation-v10-10-ee56a47479ac@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>