x86: Move P2SB from Apollo Lake to a more generic location

The Primary to Sideband Bridge (P2SB) is not specific to Apollo Lake, so
move its driver to a common location within arch/x86.

Signed-off-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/cpu/apollolake/Kconfig b/arch/x86/cpu/apollolake/Kconfig
index a760e0a..145b8cb 100644
--- a/arch/x86/cpu/apollolake/Kconfig
+++ b/arch/x86/cpu/apollolake/Kconfig
@@ -40,6 +40,7 @@
 	imply INTEL_GPIO
 	imply SMP
 	imply HAVE_ITSS
+	imply HAVE_P2SB
 
 if INTEL_APOLLOLAKE