Makefile: Change default make target to "parisc"

"parisc" is the default target when using this SeaBIOS-hppa git
repository. Change it accordingly, which then allows us to just run
"make" instead of "make parisc".

Requested-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/Makefile b/Makefile
index 3a7e119..5723653 100644
--- a/Makefile
+++ b/Makefile
@@ -101,7 +101,8 @@
 target-$(CONFIG_COREBOOT) += $(OUT)bios.bin.elf
 target-$(CONFIG_BUILD_VGABIOS) += $(OUT)vgabios.bin
 
-all: $(target-y)
+# all: $(target-y)
+all: parisc
 
 parisc: FORCE
 ifneq "$(CONFIG_PARISC)" "y"