TSP: add PIE support

This implementation simply mimics that of BL31.

Change-Id: Ibbaa4ca012d38ac211c52b0b3e97449947160e07
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index cac7e31..fc45455 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -213,7 +213,7 @@
 
 -  ``ENABLE_PIE``: Boolean option to enable Position Independent Executable(PIE)
    support within generic code in TF-A. This option is currently only supported
-   in BL2_AT_EL3 and BL31. Default is 0.
+   in BL2_AT_EL3, BL31, and BL32 (TSP). Default is 0.
 
 -  ``ENABLE_PMF``: Boolean option to enable support for optional Performance
    Measurement Framework(PMF). Default is 0.