lava-expect: fix successes strings in interactive actions

Fixes some wrongly placed successes strings and instead use only
prompts for better readability. Also, fix and re-phrase some
paragraphs in the readme section for better understanding.

Signed-off-by: Leonardo Sandoval <leonardo.sandoval@linaro.org>
Change-Id: Ia4a8f0a771d23d45f77778d3bfa1b28cc9051d34
diff --git a/lava-expect/tftf.exp b/lava-expect/tftf.exp
index 243f7cd..6c7e8fd 100644
--- a/lava-expect/tftf.exp
+++ b/lava-expect/tftf.exp
@@ -9,10 +9,14 @@
 source $ci_root/lava-expect/trusted-firmware.inc
 
 prompt='Booting trusted firmware test framework'
-successes='Running at NS-EL(1|2)'
-expect_string+=("i;${prompt};${successes}")
+expect_string+=("i;${prompt}")
+
+prompt='Running at NS-EL(1|2)'
+expect_string+=("i;${prompt}")
 
 prompt='Tests Failed  : 0'
-successes='Exiting tests.'
+expect_string+=("i;${prompt}")
+
+prompt='Exiting tests.'
 failures='Tests Passed  : 0'
-expect_string+=("i;${prompt};${successes};${failures}")
+expect_string+=("i;${prompt};;${failures}")