contrib/plugins/cache.c: Remove redundant check of l2_access

contrib/plugins/cache.c: Remove redundant check of l2_access

In append_stats_line(), we have an expression
   l2_access ? l2_miss_rate : 0.0
But this is inside an if (l2_access && l2_misses) { ... } block,
so Coverity points out that the false part of the ?: is dead code.

Remove the unnecessary test.

Resolves: Coverity CID 1522458
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240725164851.1930964-1-peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240729144414.830369-12-alex.bennee@linaro.org>