char: misc: Adapt and add test cases for simple minor space division

char: misc: Adapt and add test cases for simple minor space division

Adapt and add test cases for next change which regards minor whose
value > macro MISC_DYNAMIC_MINOR as invalid parameter when register
miscdevice, hence get a simple minor space division below:

<  MISC_DYNAMIC_MINOR: fixed minor code
== MISC_DYNAMIC_MINOR: indicator to request dynamic minor code
>  MISC_DYNAMIC_MINOR: dynamic minor code requested

Signed-off-by: Zijun Hu <zijun.hu@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250714-rfc_miscdev-v6-2-2ed949665bde@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>