common/fdt_support.c: Fix compile warnings

Commit a6bd9e83 "FDT: Add fixup support for multiple banks of memory"
removed code but forgot to remove the variables used by it, resulting
in warnings:

fdt_support.c: In function 'fdt_fixup_memory_banks':
fdt_support.c:399: warning: unused variable 'sizecell'
fdt_support.c:399: warning: unused variable 'addrcell'

Remove the declarations, too.
Signed-off-by: NWolfgang Denk <wd@denx.de>

common/fdt_support.c

@@ -396,7 +396,6 @@ int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
 	int addr_cell_len, size_cell_len, len;
 	u8 tmp[banks * 8];
 	int bank;
-	const u32 *addrcell, *sizecell;
 
 	err = fdt_check_header(blob);
 	if (err < 0) {