modules: Kconfig.simplelink: Remove POSIX_API, use fine-grained opts

PR #18780 introduces a way to decouple pthread support from the general
CONFIG_POSIX_API global switch. This commit modifies the build of
SimpleLink components to take advantage of it, since SimpleLink
libraries only require pthread, sem, clock, and sleep support, not
entire POSIX API.

This fixes the build errors in the http_get sample introduced
by the merge of #18736. As such, this patch also removes
cc3220sf_launchxl exclude from sample.yaml of that sample.

Signed-off-by: Vincent Wan <vincent.wan@linaro.org>
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
diff --git a/modules/Kconfig.simplelink b/modules/Kconfig.simplelink
index 9bbc40d..b2fca60 100644
--- a/modules/Kconfig.simplelink
+++ b/modules/Kconfig.simplelink
@@ -13,8 +13,8 @@
 	depends on MULTITHREADING
 	select NEWLIB_LIBC
 	select ERRNO
-	select POSIX_API
 	select PTHREAD_IPC
+	select POSIX_CLOCK
 	help
 	  Build the SimpleLink host driver
 
diff --git a/samples/net/sockets/http_get/sample.yaml b/samples/net/sockets/http_get/sample.yaml
index d3ca1d3..695f9af 100644
--- a/samples/net/sockets/http_get/sample.yaml
+++ b/samples/net/sockets/http_get/sample.yaml
@@ -13,7 +13,6 @@
       - CONFIG_NET_SOCKETS_POSIX_NAMES=y
     # Forcibly defines CONFIG_POSIX_API, which is incompatible with
     # CONFIG_NET_SOCKETS_POSIX_NAMES.
-    platform_exclude: cc3220sf_launchxl cc3235sf_launchxl
   sample.net.sockets.http_get.posix:
     filter: not CONFIG_NET_SOCKETS_OFFLOAD
     extra_configs: