doc: add missing doc files to EXTRA_DIST

Add doc/coding_standard_c.md and doc/logging.md to
EXTRA_DIST to include them in the package.

Fixes: #1122

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
diff --git a/Makefile.am b/Makefile.am
index f47dd80..7cf596d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -309,6 +309,8 @@
 
 EXTRA_DIST += \
     doc/doxygen.dox \
+    doc/coding_standard_c.md \
+    doc/logging.md \
     man/man-postlude.troff \
     man/Tss2_Tcti_Device_Init.3.in \
     man/Tss2_Tcti_Mssim_Init.3.in \