boot/barebox/Config.in: source argument needs quotation marks

Fixes the following error/warnings with kconfig from linux-6.9-rc5:

  boot/barebox/Config.in:79: syntax error
  boot/barebox/Config.in:79:warning: ignoring unsupported character '/'
  boot/barebox/Config.in:79:warning: ignoring unsupported character '/'
  boot/barebox/Config.in:79:warning: ignoring unsupported character '/'
  boot/barebox/Config.in:79:warning: ignoring unsupported character '.'
  boot/barebox/Config.in:79: invalid statement
  boot/barebox/Config.in:93: syntax error
  boot/barebox/Config.in:93:warning: ignoring unsupported character '/'
  boot/barebox/Config.in:93:warning: ignoring unsupported character '/'
  boot/barebox/Config.in:93:warning: ignoring unsupported character '/'
  boot/barebox/Config.in:93:warning: ignoring unsupported character '.'
  boot/barebox/Config.in:93: invalid statement

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit e86aec1663357a9f1f7de56129dfd1ab1c5d2cda)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

boot/barebox/Config.in

@@ -76,7 +76,7 @@ config BR2_TARGET_BAREBOX_CUSTOM_GIT_VERSION
 
 endif
 
-source boot/barebox/barebox/Config.in
+source "boot/barebox/barebox/Config.in"
 
 menuconfig BR2_TARGET_BAREBOX_AUX
 	bool "Build barebox with an auxiliary config"
@@ -90,7 +90,7 @@ menuconfig BR2_TARGET_BAREBOX_AUX
 
 if BR2_TARGET_BAREBOX_AUX
 
-source boot/barebox/barebox-aux/Config.in
+source "boot/barebox/barebox-aux/Config.in"
 
 endif