ALSA: scarlett2: Retrieve useful flash segment numbers

Call SCARLETT2_USB_INFO_FLASH and SCARLETT2_USB_INFO_SEGMENT to find
the App_Settings and App_Upgrade flash segment numbers, and store them
in the scarlett2_data struct. These will be used later to implement
reset to factory defaults and firmware upgrade functions.

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/70f0108a9cf99b69f7aa920c4bcdb0cf4bf3da98.1703001053.git.g@b4.vu


Signed-off-by: Takashi Iwai <tiwai@suse.de>