staging/et131x: fix et131x_rx_dma_disable halt_status usage

staging/et131x: fix et131x_rx_dma_disable halt_status usage

Commit 1bd751c1abc1029e8a0ae63ef4f19357c735a2a3
("Staging: et131x: Clean up rxdma_csr") changed csr from bitfield to
u32, but failed to convert 2 uses of halt_status bit. It did:

- if (csr.bits.halt_status != 1)
+ if ((csr & 0x00020000) != 1)

which is wrong, because second version is always true.
Fix it.

This bug was found by coccinelle (http://coccinelle.lip6.fr/).

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>