ipq806x: base-files: asrock: fix bootcount include

ipq806x: base-files: asrock: fix bootcount include

Fixes following warning message during image building process:

 Finalizing root filesystem...
 root-ipq806x/lib/upgrade/asrock.sh: line 1: /lib/functions.sh: No such file or directory
 Enabling boot
 root-ipq806x/lib/upgrade/asrock.sh: line 1: /lib/functions.sh: No such file or directory
 Enabling bootcount

Fixes #9350

Fixes: 98b86296e67d ("ipq806x: add support for ASRock G10")
Signed-off-by: Petr Štetiar <ynezz@true.cz>
(cherry picked from commit fc317a190c930c9c338bd07c2e323b6b9eaa1f07)