ppc4xx: update PMC440 board support

- switch to GENERIC_BOARD
- fix env support from eeprom

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
diff --git a/board/esd/pmc440/cmd_pmc440.c b/board/esd/pmc440/cmd_pmc440.c
index 3481e46..40b135f 100644
--- a/board/esd/pmc440/cmd_pmc440.c
+++ b/board/esd/pmc440/cmd_pmc440.c
@@ -347,16 +347,16 @@
 		return 1;
 	}
 
-	base = gd->bd->bi_memsize;
+	base = (u32)gd->ram_size;
 #if defined(CONFIG_LOGBUFFER)
 	base -= LOGBUFF_LEN + LOGBUFF_OVERHEAD;
 #endif
 	/*
-	 * gd->bd->bi_memsize == physical ram size - CONFIG_SYS_MEM_TOP_HIDE
+	 * gd->ram_size == physical ram size - CONFIG_SYS_MEM_TOP_HIDE
 	 */
 	param = base - (pram << 10);
 	printf("PARAM: @%08x\n", param);
-	debug("memsize=0x%08x, base=0x%08x\n", (u32)gd->bd->bi_memsize, base);
+	debug("memsize=0x%08x, base=0x%08x\n", (u32)gd->ram_size, base);
 
 	/* clear entire PA ram */
 	memset((void*)param, 0, (pram << 10));