drm/i915/gt: Do release kernel context if breadcrumb measure fails

Commit fb5970da ("drm/i915/gt: Use the kernel_context to measure the
breadcrumb size") reordered some operations inside engine_init_common()
and added an error unwind path to that function.  In that path, a
reference to a kernel context candidate supposed to be released on error
was put, but the context, pinned when created, was not unpinned first.
Fix it by replacing intel_context_put() with destroy_pinned_context()
introduced later by commit b436a5f8 ("drm/i915/gt: Track all timelines
created using the HWSP").

Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210507144251.376538-1-janusz.krzysztofik@linux.intel.com