[U-Boot] [PATCH v3] doc: README.mxs: Add instruction to install 'libssl-dev'

[Fabio Estevam]

Since commit bce883707 (ARM: mxs: tools: Add mkimage support for MXS bootstream)
the following build error is seen when doing a MAKEALL build:

$ ./MAKEALL mx28evk
Configuring for mx28evk - Board: mx28evk, Options: ENV_IS_IN_MMC
mxsimage.c:18:25: fatal error: openssl/evp.h: No such file or directory

Add an entry about the need of installing the 'libssl-dev' package.

Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
Changes since v2:
- Use "Debian-based" 
Changes since v1:
- Do not remove the 'elftosb' text.

 doc/README.mxs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/doc/README.mxs b/doc/README.mxs
index 5d9e72f..1e5bc5c 100644
--- a/doc/README.mxs
+++ b/doc/README.mxs
@@ -63,6 +63,11 @@ copy the binary by hand:
 Make sure the "elftosb" binary can be found in your $PATH, in this case this
 means "/usr/local/bin/" has to be in your $PATH.
 
+Install the 'libssl-dev' package as well. On a Debian-based distribution, this
+package can be installed as follows:
+
+	$ sudo apt-get install libssl-dev
+
 2) Compiling U-Boot for a MXS based board
 -------------------------------------------
 
-- 
1.8.1.2