rockchip: Prevent macro expansion in paths

Instead of stringizing the paths to binary files, add them as string
defines on the command line (e.g. -DFOO=\"BAR\" instead of -DFOO=BAR).
This prevents macros from being expanded inside the string value itself.
For example, -DFOO=/path/with-linux-in-it would have been expanded to
"/path/with-1-in-it" because `linux=1` is one of the standard GCC
defines.

Change-Id: I7b65df3c9930faed4f1aff75ad726982ae3671e6
Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
diff --git a/plat/rockchip/rk3399/drivers/dp/cdn_dp.c b/plat/rockchip/rk3399/drivers/dp/cdn_dp.c
index aa71fde..a8773f4 100644
--- a/plat/rockchip/rk3399/drivers/dp/cdn_dp.c
+++ b/plat/rockchip/rk3399/drivers/dp/cdn_dp.c
@@ -18,7 +18,7 @@
 	".global hdcp_handler\n"
 	".balign 4\n"
 	"hdcp_handler:\n"
-	".incbin \"" __XSTRING(HDCPFW) "\"\n"
+	".incbin \"" HDCPFW "\"\n"
 	".type hdcp_handler, %function\n"
 	".size hdcp_handler, .- hdcp_handler\n"
 	".popsection\n"