memory_bus: Move related declarations into new `chipdrivers/memory_bus.h`

Change-Id: I2bef65de77860d049ec3d9938ae777c5f929c258
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/438
diff --git a/sst49lfxxxc.c b/sst49lfxxxc.c
index a69ab75..d03b428 100644
--- a/sst49lfxxxc.c
+++ b/sst49lfxxxc.c
@@ -17,7 +17,7 @@
  */
 
 #include "flash.h"
-#include "chipdrivers.h"
+#include "chipdrivers/memory_bus.h"
 
 int erase_sector_49lfxxxc(struct flashctx *flash, unsigned int address,
 			  unsigned int sector_size)