Convert CONFIG_SKIP_LOWLEVEL_INIT et al to Kconfig

This converts the following to Kconfig:
   CONFIG_SKIP_LOWLEVEL_INIT
   CONFIG_SKIP_LOWLEVEL_INIT_ONLY

In order to do this, we need to introduce SPL and TPL variants of these
options so that we can clearly disable these options only in SPL in some
cases, and both instances in other cases.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index 3112664..6998a50 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -72,6 +72,7 @@
 	select CPU_V7A
 	select SPL
 	select SPL_BOARD_INIT if SPL
+	select SPL_SKIP_LOWLEVEL_INIT_ONLY if SPL
 	select SUPPORT_SPL
 	select TEGRA_CLKRST
 	select TEGRA_COMMON