net: hibmcge: move dma_rmb() after dma_sync_single_for_cpu() in RX path

net: hibmcge: move dma_rmb() after dma_sync_single_for_cpu() in RX path

The dma_rmb() barrier was placed before dma_sync_single_for_cpu(), which
is incorrect. DMA sync must complete first to make the buffer accessible
to the CPU, then the rmb barrier ensures subsequent descriptor reads
observe the latest data written by the hardware.

Reorder the operations so dma_sync_single_for_cpu() is called before
dma_rmb() to guarantee the driver reads consistent data from the DMA
buffer.

Fixes: f72e25594061 ("net: hibmcge: Implement rx_poll function to receive packets")
Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Link: https://patch.msgid.link/20260525144525.94884-3-shaojijie@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>