[S390] zcrypt driver Makefile, Kconfig and monolithic build.

The Makefile and Kconfig changes should be obvious. The monolithic
build option is there to create an old-style z90crypt module for
backward compatability to older distributions.

Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>