This reverts commit 906b40b2 ("dmaengine: stm32-mdma: Add a check on
read_u32_array")

As stated by bindings "st,ahb-addr-masks" is optional.
The statement inserted by this commit makes this property
mandatory and prevents MDMA to be probed in case property not present.
Signed-off-by: NPierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: NVinod Koul <vkoul@kernel.org>