[PATCH] mtd: spinand: Fix build with gcc < 7.5

[Miquel Raynal]

__VA_OPT__ is a macro that is useful when some arguments can be present
or not to entirely skip some part of a definition. Unfortunately, it
is a too recent addition that some of the still supported old GCC
versions do not know about, and is anyway not part of C11 that is the
version used in the kernel.

Find a trick to remove this macro, typically '__VA_ARGS__ + 0' is a
workaround used in netlink.h which works very well here, as we either
expect:
- 0
- A positive value
- No value, which means the field should be 0.

Reported-by: kernel test robot <lkp at intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202503181330.YcDXGy7F-lkp@intel.com/
Fixes: 7ce0d16d5802 ("mtd: spinand: Add an optional frequency to read from cache macros")
Cc: stable at vger.kernel.org
Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 include/linux/mtd/spinand.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
index 83301ef11aa9..0bb06aeffa62 100644
--- a/include/linux/mtd/spinand.h
+++ b/include/linux/mtd/spinand.h
@@ -67,7 +67,7 @@
 		   SPI_MEM_OP_ADDR(2, addr, 1),				\
 		   SPI_MEM_OP_DUMMY(ndummy, 1),				\
 		   SPI_MEM_OP_DATA_IN(len, buf, 1),			\
-		   __VA_OPT__(SPI_MEM_OP_MAX_FREQ(__VA_ARGS__)))
+		   SPI_MEM_OP_MAX_FREQ(__VA_ARGS__ + 0))
 
 #define SPINAND_PAGE_READ_FROM_CACHE_FAST_1S_1S_1S_OP(addr, ndummy, buf, len) \
 	SPI_MEM_OP(SPI_MEM_OP_CMD(0x0b, 1),				\
-- 
2.48.1