The simplest fix is to export that helper function.
Fixes: 8b0c93c20ef7 ("perf/arm-cci: Allow building as a module") Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Will Deacon <will.deacon@arm.com>