sandbox: swap_case: Increase number of base address regs

At present the code overruns the bar[] array. Fix this.

At the same time, drop the leading / from the "/spl" path so that we can
run U-Boot SPL with:

   spl/u-boot-spl

rather than requiring:

   /path/to/spl/u-boot-spl

Reported-by: Coverity (CID: 131199)

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

drivers/misc/swap_case.c

@@ -21,7 +21,7 @@
  */
 struct swap_case_platdata {
 	u16 command;
-	u32 bar[2];
+	u32 bar[6];
 };
 
 #define offset_to_barnum(offset)	\