perf/arm_dmc620_pmu: Fix error return code in dmc620_pmu_device_probe()

perf/arm_dmc620_pmu: Fix error return code in dmc620_pmu_device_probe()

BugLink: https://bugs.launchpad.net/bugs/1919492
[ Upstream commit c8e3866836528a4ba3b0535834f03768d74f7d8e ]

Fix to return negative error code -ENOMEM from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 53c218da220c ("driver/perf: Add PMU driver for the ARM DMC-620 memory controller")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20210312080421.277562-1-weiyongjun1@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>