perf: arm-ni: Fix missing platform_set_drvdata()

Add missing platform_set_drvdata in arm_ni_probe(), otherwise
calling platform_get_drvdata() in remove returns NULL.

Fixes: 4d5a7680 ("perf: Add driver for Arm NI-700 interconnect PMU")
Signed-off-by: Hongbo Yao <andy.xu@hj-micro.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20250401054248.3985814-1-andy.xu@hj-micro.com


Signed-off-by: Will Deacon <will@kernel.org>