zephyr/module.yml: enable use of kconfig-ext

Change to using kconfig-ext which means we'll look in the
zephyr repo for kconfig files. Change also module name to
'hal_st' for the sake of understandability.

Signed-off-by: Armando Visconti <armando.visconti@st.com>

Author: avisconti

zephyr/module.yml

@@ -1,2 +1,4 @@
+name: hal_st
 build:
   cmake: .
+  kconfig-ext: True