nvmet: pci-epf: fix DMA channel debug print

nvmet: pci-epf: fix DMA channel debug print

Currently, nvmet_pci_epf_init_dma() has two dev_dbg() calls intended to
print debug information about the DMA channels for RX and TX. However,
both calls mistakenly are made for the TX channel. Fix it by referreing
to 'nvme_epf->rx_chan' and 'nvme_epf->tx_chan' and instead of the local
variable 'chan'.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>