[U-Boot] Build error of u-boot mater branch

[Bo Shen]

Hi All,
  When build u-boot master branch, I meet the following of error.
---8>---
lib/rsa/rsa-sign.c:26:25: fatal error: openssl/rsa.h: No such file or
directory
---<8---

The master git commit id I build is:
1b9591c2375d59be333c98c760e06605007e20c3 (ColdFire: Update the
arch_global_date changes for mcf5441x)

And lib/rsa/rsa-sign.c commit id is:
19c402afa2e1190f596f35a84ac049b10d814f1f (image: Add RSA support for
image signing)

Best Regards,
Bo Shen