[][openwrt][common][bsp][Add ignore item of checkpatch]

[Description]
Add MACRO_WITH_FLOW_CONTROL to .checkpatch.conf as it conflicts with
MULTISTATEMENT_MACRO_USE_DO_WHILE

Macro with flow control is used everywhere, including linux kernel.

[Release-log]
N/A

Change-Id: Ie19196941183f3824fd00684e21fd6fa0cd3c890
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/9372504
diff --git a/.checkpatch.conf b/.checkpatch.conf
index 9a6a9a8..45bf9d0 100644
--- a/.checkpatch.conf
+++ b/.checkpatch.conf
@@ -7,4 +7,5 @@
 --ignore BLOCK_COMMENT_STYLE
 --ignore REPEATED_WORD
 --ignore SPDX_LICENSE_TAG
---ignore CONST_STRUCT
\ No newline at end of file
+--ignore CONST_STRUCT
+--ignore MACRO_WITH_FLOW_CONTROL