ralink: mt76x8: fix compilation warning in esw driver

ralink: mt76x8: fix compilation warning in esw driver

Fix compilation warning for debug string in esw driver:
drivers/net/ethernet/ralink/esw_rt3050.c:1535:9: note: in expansion of macro 'dev_info'
 1535 |         dev_info(&pdev->dev, "mediatek esw at 0x%08lx, irq %d initialized\n",
      |         ^~~~~~~~
drivers/net/ethernet/ralink/esw_rt3050.c:1535:53: note: format string is defined here
 1535 |         dev_info(&pdev->dev, "mediatek esw at 0x%08lx, irq %d initialized\n",
      |                                                 ~~~~^
      |                                                     |
      |                                                     long unsigned int
      |                                                 %08p
cc1: all warnings being treated as errors

Fix unused variable causing compilation warning:
drivers/net/ethernet/ralink/esw_rt3050.c: In function 'esw_interrupt':
drivers/net/ethernet/ralink/esw_rt3050.c:769:13: error: unused variable 'i' [-Werror=unused-variable]
  769 |         int i;
      |             ^
cc1: all warnings being treated as errors

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>