check_whence.py: Add support for filenames with spaces in them

check_whence.py: Add support for filenames with spaces in them

Some vendors save a couple of cents by not including an eeprom for
wifi parameters on their boards. Instead the driver loads these board
specific parameters through the request_firmware mechanism.

Since these are board specific the filenames also must be board specific,
on x86 DMI strings are used for this and the wifi chipname is postfixed
with $sys_vendor-$product_name from the DMI tables. These DMi variables
may contain spaces.

This commit adds support to check_whence.py for filenames with spaces
in them, after this commit these can be specified by putting double-quotes
around them, e.g "name with spaces.bin".

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Josh Boyer <jwboyer@kernel.org>