Adding gitattributes file for managing line ending conversions

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

.gitattributes

@@ -0,0 +1,20 @@
+# Set the default behavior, in case people don't have core.autocrlf set.
+* text=auto
+
+# Explicitly declare text files you want to always be normalized and converted
+# to native line endings on checkout.
+*.c text
+*.cpp text
+*.h text
+*.s text
+*.S text
+*.ld text
+*.txt text
+*.xml text
+*.py text
+*.md text
+*.json text
+
+# Denote all files that are truly binary and should not be modified.
+*.png binary
+*.jpg binary