tegra: Replace 'Norrin' with 'Nyan-big' and fix typo

With the rename the MAINTAINER file was not updated. Fix it and the
'Chrombook' typo in Kconfig.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/mach-tegra/tegra124/Kconfig b/arch/arm/mach-tegra/tegra124/Kconfig
index 6579e3f..f3324ff 100644
--- a/arch/arm/mach-tegra/tegra124/Kconfig
+++ b/arch/arm/mach-tegra/tegra124/Kconfig
@@ -10,7 +10,7 @@
 	select CPU_V7_HAS_VIRT if !SPL_BUILD
 
 config TARGET_NYAN_BIG
-	bool "Google/NVIDIA Nyan-big Chrombook"
+	bool "Google/NVIDIA Nyan-big Chromebook"
 	help
 	  Nyan Big is a Tegra124 clamshell board that is very similar
 	  to venice2, but it has a different panel, the sdcard CD and WP