Build: Fix documentation generation issues

This patch fixes some issues related to the documents
generation, in particular:

-- Fix an issue with pdflatex generation for case
   sensitive shells such as bash
-- Introduce support for png and jpg images in
   rst documents

Change-Id: I379ac3bedae386c1ad7de96380d7d0fc64fb40fd
Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
diff --git a/cmake/Common/BuildSphinxDoc.cmake b/cmake/Common/BuildSphinxDoc.cmake
index 09bd30c..68887ff 100644
--- a/cmake/Common/BuildSphinxDoc.cmake
+++ b/cmake/Common/BuildSphinxDoc.cmake
@@ -121,7 +121,7 @@
 
 	#If PDF documentation is being made.
 	if (PDFLATEX_COMPILER)
-		set(_PDF_FILE "${SPHINXCFG_OUTPUT_PATH}/latex/tf-m.pdf")
+		set(_PDF_FILE "${SPHINXCFG_OUTPUT_PATH}/latex/TF-M.pdf")
 
 		add_custom_command(OUTPUT "${SPHINXCFG_OUTPUT_PATH}/latex"
 			COMMAND "${SPHINX_EXECUTABLE}" -c "${SPHINXCFG_OUTPUT_PATH}" -b latex "${SPHINX_TMP_DOC_DIR}" "${SPHINXCFG_OUTPUT_PATH}/latex"