dmaengine: stm32-dma: Fix redundant call to platform_get_irq

commit e4054393 upstream.

Commit c6504be5 ("dmaengine: stm32-dma: Fix unsigned variable compared
with zero") duplicated the call to platform_get_irq.
So remove the first call to platform_get_irq.

Fixes: c6504be5 ("dmaengine: stm32-dma: Fix unsigned variable compared with zero")
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>