smartmontools: fix dependency declaration by f5f49e4

smartmontools: fix dependency declaration by f5f49e4

Fix the dependency declaration by removing the unnecessary/illegal
commas:

>  WARNING: Makefile 'package/feeds/packages/smartmontools/Makefile' has a dependency on 'smartd,', which does not exist
>  WARNING: Makefile 'package/feeds/packages/smartmontools/Makefile' has a dependency on 'nail,', which does not exist
>  tmp/.config-package.in:153368:warning: ignoring unsupported character ','
>  tmp/.config-package.in:153373:warning: ignoring unsupported character ','

Signed-off-by: Hannu Nyman <redacted>