accel/ivpu: Add test modes to toggle clock relinquish disable

Add IVPU_TEST_MODE_CLK_RELINQ_[DISABLE|ENABLE] that overrides
workaround for disabling clock relinquish for testing purposes.

Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Signed-off-by: Karol Wachowski <karol.wachowski@intel.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250204084622.2422544-6-jacek.lawrynowicz@linux.intel.com