ci: mynewt: Download nrfx from separate repository

Mynewt used to have copy of nrfx.
Now nrfx is taken from original repository and since some CI
targets want to build for NRF MCUs nrfx repository nees to be
downloaded.

Signed-off-by: Jerzy Kasenberg <jerzy.kasenberg@codecoup.pl>
diff --git a/ci/mynewt_install.sh b/ci/mynewt_install.sh
index ea7e753..b7b065e 100755
--- a/ci/mynewt_install.sh
+++ b/ci/mynewt_install.sh
@@ -34,6 +34,10 @@
     mkdir -p repos/apache-mynewt-core
     git clone --depth=1 https://github.com/apache/mynewt-core repos/apache-mynewt-core
     [[ $? -ne 0 ]] && exit 1
+
+    # nrfx is now taken from original repository
+    git clone --depth=1 --branch v2.8.0 https://github.com/NordicSemiconductor/nrfx.git repos/nordic-nrfx
+    [[ $? -ne 0 ]] && exit 1
 }
 
 arm_toolchain_install() {