powerpc: kill PPC_OF

We have set CONFIG_PPC_OF to always 'y' in commit 0a498d96a332
("powerpc: set CONFIG_PPC_OF=y always for ARCH=powerpc") nine years
ago. And the arch/ppc also has gone away for many years. The OF
functionality was also moved to a common place and be used by many
archs. So it does make no sense to keep such a option in the current
kernel. Just kill it.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index ec2e40f..bfd823a 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -117,7 +117,7 @@
 
 config BOOTX_TEXT
 	bool "Support for early boot text console (BootX or OpenFirmware only)"
-	depends on PPC_OF && PPC_BOOK3S
+	depends on PPC_BOOK3S
 	help
 	  Say Y here to see progress messages from the boot firmware in text
 	  mode. Requires either BootX or Open Firmware.