ACPI: property: Fix return value for nval == 0 in acpi_data_prop_read()

While analysing code for software and OF node for the corner case when
caller asks to read zero items in the supposed to be an array of values
I found that ACPI behaves differently to what OF does, i.e.

 1. It returns -EINVAL when caller asks to read zero items from integer
    array, while OF returns 0, if no other errors happened.

 2. It returns -EINVAL when caller asks to read zero items from string
    array, while OF returns -ENODATA, if no other errors happened.

Amend ACPI implementation to follow what OF does.

Fixes: b31384fa ("Driver core: Unified device properties interface for platform firmware")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20250203194629.3731895-1-andriy.shevchenko@linux.intel.com


[ rjw: Added empty line after a conditional ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>