[POWERPC] Select DEFAULT_UIMAGE for HPC-NET/8641

I suspect this was meant to be added like it was to a whole slew of
other u-boot based boards, but probably just fell through the cracks.

Add "select DEFAULT_UIMAGE" for the 8641/HPC-NET.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/86xx/Kconfig

@@ -8,6 +8,7 @@ choice
 config MPC8641_HPCN
 	bool "Freescale MPC8641 HPCN"
 	select PPC_I8259
+	select DEFAULT_UIMAGE
 	help
 	  This option enables support for the MPC8641 HPCN board.