jlink_spi: Reduce transfer size

The maximum transfer size is too large for some devices and
results in an USB timeout.

Change-Id: If2c00b1524ec56740bdfe290096c3546cf375d73
Signed-off-by: Marc Schink <dev@zapb.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/48379
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Miklós Márton <martonmiklosqdev@gmail.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/67855
Reviewed-by: Felix Singer <felixsinger@posteo.net>
---
M jlink_spi.c
1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/jlink_spi.c b/jlink_spi.c
index 08a9ba9..cf732b0 100644
--- a/jlink_spi.c
+++ b/jlink_spi.c
@@ -34,7 +34,7 @@
  * Maximum number of bytes that can be transferred at once via the JTAG
  * interface, see jaylink_jtag_io().
  */
-#define JTAG_MAX_TRANSFER_SIZE	(UINT16_MAX / 8)
+#define JTAG_MAX_TRANSFER_SIZE	(32768 / 8)
 
 /*
  * Default base frequency in Hz. Used when the base frequency can not be

