checkpatch.conf: new file

Disable spacing and open brace checks, as this repository follows a
different code style.

If needed, the checkpatch file can be extended with other checks:
* get the check name from the linter output, e.g. SPACING in:
  firmware/ice40-riscv/icE1usb/fw_app.c:155: ERROR:SPACING: spaces required around that '=' (ctx:VxV)
* add a new "--ignore NAME" line to the file

Related: https://gerrit.osmocom.org/c/osmo-e1-hardware/+/26841
Related: OS#5399
Change-Id: I4d2cf2eb698b8f4e54f04e62e4dbbc37146daf88
1 file changed