ppc: reduce size of Forth dictionary to 384K

gcc 9 emits a fatal error when building OpenBIOS for ppc because the size of the
generated image is greater than the available ROM area when building with -O0.

Reduce the size of the Forth dictionary from 512K to 384K to allow sufficient
space for generating OpenBIOS images suitable for debugging.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

arch/ppc/qemu/kernel.c

diff --git a/arch/ppc/qemu/kernel.c b/arch/ppc/qemu/kernel.c
index b26fba5..893ab68 100644
--- a/arch/ppc/qemu/kernel.c
+++ b/arch/ppc/qemu/kernel.c
@@ -26,8 +26,8 @@
 #include "kernel.h"
 
 #define MEMORY_SIZE	(256*1024)	/* 256K ram for hosted system */
-/* 512K for the dictionary  */
-#define DICTIONARY_SIZE (512 * 1024 / sizeof(ucell))
+/* 384K for the dictionary  */
+#define DICTIONARY_SIZE (384 * 1024 / sizeof(ucell))
 #ifdef __powerpc64__
 #define DICTIONARY_BASE 0xfff08000 /* this must match the value in ldscript! */
 #define DICTIONARY_SECTION __attribute__((section(".data.dict")))