crypto: GnuPG based MPI lib - additional sources (part 4)

Adds the multi-precision-integer maths library which was originally taken
from GnuPG and ported to the kernel by (among others) David Howells.
This version is taken from Fedora kernel 2.6.32-71.14.1.el6.
The difference is that checkpatch reported errors and warnings have been fixed.

This library is used to implemenet RSA digital signature verification
used in IMA/EVM integrity protection subsystem.

Due to patch size limitation, the patch is divided into 4 parts.

This code is unnecessary for RSA digital signature verification,
but for completeness it is included here and can be compiled,
if CONFIG_MPILIB_EXTRA is enabled.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
diff --git a/lib/Kconfig b/lib/Kconfig
index 4af07ec..d411de5 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -283,4 +283,14 @@
 	  It is used to implement RSA digital signature verification,
 	  which is used by IMA/EVM digital signature extension.
 
+config MPILIB_EXTRA
+	bool "Multiprecision maths library - additional sources"
+	depends on MPILIB
+	help
+	  Multiprecision maths library from GnuPG.
+	  It is used to implement RSA digital signature verification,
+	  which is used by IMA/EVM digital signature extension.
+	  This code in unnecessary for RSA digital signature verification,
+	  and can be compiled if needed.
+
 endmenu