arm: spear13xx: Fix dmas cells

The "dmas" cells for the designware DMA controller need to have only 3
properties apart from the phandle: request line, src master and
destination master. But the commit 6e8887f6 updated it incorrectly
while moving from platform code to DT. Fix it.

Cc: stable@vger.kernel.org # v3.10+
Fixes: 6e8887f6 ("ARM: SPEAr13xx: Pass generic DW DMAC platform data from DT")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>