ath11k-firmware: WCN6750 hw1.0: board file for Nothing Phone (3a)

* description for what hardware this is:
A WCN6755 module found in a Nothing Phone (3a).

* origin of the board file (did you create it yourself or where you downloaded)
Extracted from the stock factory image (B4.0-251118-1551), looking at
stock logs they are loading modem/image/qca6750/bdwlan.elf.

ids to be used with the board file:
  - WCN6750 hw1.0

    + bus=ahb,qmi-chip-id=1,qmi-board-id=255,variant=Nothing_Phone_3a.elf
      sha256sum:
e7717c00ecd077a59c645412b27eea95d6076d86c56d4b20e6e8301c7938c377

    + bus=ahb,qmi-chip-id=1,qmi-board-id=255,variant=Nothing_Phone_3a.regdb
      sha256sum:
ee9eccd617b60f501da95991202a3b6bda8f464e6abb5166030f7b4c41939bf3

md5sum of each new board file to add:

    + bus=ahb,qmi-chip-id=1,qmi-board-id=255,variant=Nothing_Phone_3a.elf
      md5sum:
47611ff710c2db584d93d933c8f50bd2

    + bus=ahb,qmi-chip-id=1,qmi-board-id=255,variant=Nothing_Phone_3a.regdb
      md5sum:
4305d6ef509c0f59f71882c9a32e69bd