perf cs-etm: Don't use hard coded config bits when setting up ETMCR

perf cs-etm: Don't use hard coded config bits when setting up ETMCR

Perf only looks at attr.config when determining what was programmed into
ETMCR. These bits could theoretically be in any of the config fields.
Add a generic helper to find the value of any named format field in any
config field and then use it to get the attributes relevant to ETMCR.

The kernel will also stop publishing the ETMCR register bits in a header
[1] so preempt that by defining them here.

Move field_prep() to util.h so we can define it along side field_get().
Unfortunately FIELD_PREP() and FIELD_GET() from the kernel can't be used
as they require the mask to be a compile time constant.

[1]: https://lore.kernel.org/linux-arm-kernel/20251128-james-cs-syncfreq-v8-10-4d319764cc58@linaro.org/

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>