parisc: disable -mlong-calls compiler option for kernel modules

CONFIG_MLONGCALLS was introduced in commit
ec758f98 to overcome linker issues when linking
huge linux kernels, e.g. with many modules linked in.

But in the kernel module loader there is no support yet for the new relocation
types, which is why modules built with -mlong-calls can't be loaded.
Furthermore, for modules long calls are not really necessary, since we already
use stub sections which resolve long distance calls.

So, let's just disable this compiler option when compiling kernel modules.
Signed-off-by: Helge Deller <deller@gmx.de>

arch/parisc/Makefile

@@ -65,8 +65,10 @@ ifndef CONFIG_FUNCTION_TRACER
 endif
 
 # Use long jumps instead of long branches (needed if your linker fails to
-# link a too big vmlinux executable)
-cflags-$(CONFIG_MLONGCALLS)	+= -mlong-calls
+# link a too big vmlinux executable). Not enabled for building modules.
+ifdef CONFIG_MLONGCALLS
+KBUILD_CFLAGS_KERNEL += -mlong-calls
+endif
 
 # select which processor to optimise for
 cflags-$(CONFIG_PA7100)		+= -march=1.1 -mschedule=7100