avr32: fix building warnings caused by redefinitions of HZ

As suggested by David Howells <dhowells@redhat.com>, use
asm-generic/param.h and uapi/asm-generic/param.h for AVR32.

It also fixes building warnings caused by redefinitions of HZ:
In file included from /ws/linux/kernel/linux.git/include/uapi/linux/param.h:4,
                 from include/linux/timex.h:63,
                 from include/linux/jiffies.h:8,
                 from include/linux/ktime.h:25,
                 from include/linux/timer.h:5,
                 from include/linux/workqueue.h:8,
                 from include/linux/srcu.h:34,
                 from include/linux/notifier.h:15,
                 from include/linux/memory_hotplug.h:6,
                 from include/linux/mmzone.h:777,
                 from include/linux/gfp.h:4,
                 from arch/avr32/mm/init.c:10:
/ws/linux/kernel/linux.git/arch/avr32/include/asm/param.h:6:1: warning: "HZ" redefined
In file included from /ws/linux/kernel/linux.git/arch/avr32/include/asm/param.h:4,
                 from /ws/linux/kernel/linux.git/include/uapi/linux/param.h:4,
                 from include/linux/timex.h:63,
                 from include/linux/jiffies.h:8,
                 from include/linux/ktime.h:25,
                 from include/linux/timer.h:5,
                 from include/linux/workqueue.h:8,
                 from include/linux/srcu.h:34,
                 from include/linux/notifier.h:15,
                 from include/linux/memory_hotplug.h:6,
                 from include/linux/mmzone.h:777,
                 from include/linux/gfp.h:4,
                 from arch/avr32/mm/init.c:10:
/ws/linux/kernel/linux.git/arch/avr32/include/uapi/asm/param.h:6:1: warning: this is the location of the previous definition

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>

arch/avr32/include/asm/Kbuild

@@ -2,3 +2,4 @@
 generic-y	+= clkdev.h
 generic-y	+= exec.h
 generic-y	+= trace_clock.h
+generic-y	+= param.h

arch/avr32/include/uapi/asm/Kbuild

@@ -33,3 +33,4 @@ header-y += termbits.h
 header-y += termios.h
 header-y += types.h
 header-y += unistd.h
+generic-y += param.h