counter: Consolidate Counter extension sysfs attribute creation

Counter extensions are handled for the Device, Counts, and Signals. The
code loops through each Counter extension and creates the expected sysfs
attributes. This patch consolidates that code into functions to reduce
redundancy and make the intention of the code clearer.

Link: https://lore.kernel.org/r/6f2121cf52073028c119dbf981a8b72f3eb625d2.1664204990.git.william.gray@linaro.org/


Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/0469c3ae3fbccbca908993c78d94f221761a6a3a.1664318353.git.william.gray@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>