Stop making the ndk headers host-specific

This breaks when I enable a second host configuration for host bionic.

Make non-arch modules !Device and !Host by adding "Generic" as the zero
value. Make the SkipDeviceInstall config only apply to Device modules.

Test: out/soong/build.ninja is identical expect for comments
Change-Id: I6e2bd3814a9968554d3901a508d822d5c79d08a0
diff --git a/android/module.go b/android/module.go
index 7b35d32..6474e47 100644
--- a/android/module.go
+++ b/android/module.go
@@ -631,7 +631,7 @@
 	a.module.base().hooks.runInstallHooks(a, fullInstallPath, false)
 
 	if !a.module.base().commonProperties.SkipInstall &&
-		(a.Host() || !a.AConfig().SkipDeviceInstall()) {
+		(!a.Device() || !a.AConfig().SkipDeviceInstall()) {
 
 		deps = append(deps, a.installDeps...)
 
@@ -669,7 +669,7 @@
 	a.module.base().hooks.runInstallHooks(a, fullInstallPath, true)
 
 	if !a.module.base().commonProperties.SkipInstall &&
-		(a.Host() || !a.AConfig().SkipDeviceInstall()) {
+		(!a.Device() || !a.AConfig().SkipDeviceInstall()) {
 
 		a.ModuleBuild(pctx, ModuleBuildParams{
 			Rule:      Symlink,