x86/Kconfig: Make CMDLINE_OVERRIDE depend on non-empty CMDLINE

When trying to boot an allmodconfig kernel that is built with
KCONFIG_ALLCONFIG=$(pwd)/arch/x86/configs/x86_64_defconfig, it doesn't
boot since CONFIG_CMDLINE_OVERRIDE gets enabled and that requires the
user to pass the full cmdline to CONFIG_CMDLINE.

Change so that CONFIG_CMDLINE_OVERRIDE gets set only if CONFIG_CMDLINE
is set to something except an empty string.

 [ bp: touchup. ]

Signed-off-by: Anders Roxell <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: roxell

arch/x86/Kconfig

@@ -2418,7 +2418,7 @@ config CMDLINE
 
 config CMDLINE_OVERRIDE
 	bool "Built-in command line overrides boot loader arguments"
-	depends on CMDLINE_BOOL
+	depends on CMDLINE_BOOL && CMDLINE != ""
 	---help---
 	  Set this option to 'Y' to have the kernel ignore the boot loader
 	  command line, and use ONLY the built-in command line.