net: stmmac: Add support for TX/RX channel interrupt

Enable TX/RX channel interrupt registration for MAC that interrupts CPU
through shared peripheral interrupt (SPI).

Per channel interrupts and interrupt-names are registered through,
Eg: 4 tx and 4 rx channels:
interrupts = <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
             <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
             <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
             <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
             <GIC_SPI 104 IRQ_TYPE_LEVEL_HIGH>;
             <GIC_SPI 105 IRQ_TYPE_LEVEL_HIGH>;
             <GIC_SPI 106 IRQ_TYPE_LEVEL_HIGH>;
             <GIC_SPI 107 IRQ_TYPE_LEVEL_HIGH>;
interrupt-names = "dma_tx0",
                  "dma_tx1",
                  "dma_tx2",
                  "dma_tx3",
                  "dma_rx0",
                  "dma_rx1",
                  "dma_rx2",
                  "dma_rx3";

Signed-off-by: Teoh Ji Sheng <ji.sheng.teoh@intel.com>
Signed-off-by: Swee Leong Ching <leong.ching.swee@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>