[][kernel][mt7988][eip197][Fix memory leaks of eip197_load_firmwares]

[Description]
Fix memory leaks of eip197_load_firmwares.
Add release_firmware to release firmware resource.

[Release-log]
N/A

Change-Id: I970c8d2161d3bd309e49495d4a2685b32e14233e
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6701917
1 file changed