s390: Compile kernel with -fPIC and link with -no-pie

When the kernel is built with CONFIG_PIE_BUILD option enabled it
uses dynamic symbols, for which the linker does not allow more
than 64K number of entries. This can break features like kpatch.

Hence, whenever possible the kernel is built with CONFIG_PIE_BUILD
option disabled. For that support of unaligned symbols generated by
linker scripts in the compiler is necessary.

However, older compilers might lack such support. In that case the
build process resorts to CONFIG_PIE_BUILD option-enabled build.

Compile object files with -fPIC option and then link the kernel
binary with -no-pie linker option.

As result, the dynamic symbols are not generated and not only kpatch
feature succeeds, but also the whole CONFIG_PIE_BUILD option-enabled
code could be dropped.

[ agordeev: Reworded the commit message ]

Suggested-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>