spi: sirf: enable RX_IO_DMA_INT interrupt

spi: sirf: enable RX_IO_DMA_INT interrupt

in spi interrupt handler, we need check RX_IO_DMA status to ensure
rx fifo have received the specify count data.

if not set, the while statement in spi isr function will keep loop,
at last, make the kernel hang.

[The code is actually there in the interrupt handler but apparently it
needs the interrupt unmasking so the handler sees the status -- broonie]

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org