msm: emac: Update IRQ resource handling

Update code to get IRQs as platform resource.
Also embed the IRQ information in ethernet adapter data structure
so as to support multiple EMAC hardware instances by the driver.

Change-Id: I16d0ee0777e3a183bac4b306f9b79feab0670094
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>