PCI: xilinx-xdma: Remove redundant dev_err()

There is no need to call the dev_err() function directly to print a
custom message when handling an error from either the platform_get_irq()
or platform_get_irq_byname() functions as both are going to display an
appropriate error message in case of a failure.

  ./drivers/pci/controller/pcie-xilinx-dma-pl.c:688:2-9: line 688 is redundant because platform_get_irq() already prints an error
  ./drivers/pci/controller/pcie-xilinx-dma-pl.c:702:2-9: line 702 is redundant because platform_get_irq() already prints an error

Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7074
Link: https://lore.kernel.org/linux-pci/20231030061242.51475-1-yang.lee@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>