dpaa2-switch: fix the error path in dpaa2_switch_rx()

dpaa2-switch: fix the error path in dpaa2_switch_rx()

In case of an error in dpaa2_switch_rx(), the dpaa2_switch_free_fd()
function is called in order to free the FD. This is incorrect since the
dpaa2_switch_free_fd() is intended to be used on Tx frame descriptors,
meaning that it expects in the software annotation area of the FD data
to find a valid skb pointer on which to call dev_kfree_skb().

Fix this by extracting the dma_unmap_page() from
dpaa2_switch_build_linear_skb() directly into the dpaa2_switch_rx()
function. This allows us to directly use free_pages() in case of an
error before an SKB was created and kfree_skb() afterwards.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://patch.msgid.link/20260528173452.1953102-3-ioana.ciornei@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>