perf/x86/amd/uncore: Fix the return value of amd_uncore_df_event_init() on error

perf/x86/amd/uncore: Fix the return value of amd_uncore_df_event_init() on error

If amd_uncore_event_init() fails, return an error irrespective of the
pmu_version. Setting hwc->config should be safe even if there is an
error so use this opportunity to simplify the code.

Closes: https://lore.kernel.org/all/aTaI0ci3vZ44lmBn@stanley.mountain/
Fixes: d6389d3ccc13 ("perf/x86/amd/uncore: Refactor uncore management")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/076935e23a70335d33bd6e23308b75ae0ad35ba2.1765268667.git.sandipan.das@amd.com