fix-up GIANFAR driver timer bug

[sun]

Repeat executing a command series like the attached descript will cause
system hanging or kernel panic shown below on a GIANFAR used system.
The attached patch is for fix the above issue.
The issue and the solution have been confirmed on
MPC8560ADS and MPC85555CDS evaluation boards.

----------
-sh-3.00# ./net_setting.sh
eth1 setting start
###set ip-address

###net Trying to free free IRQ103
down

###set MAC address

###net up
kernel BUG in cascade at kernel/timer.c:419!
Oops: Exception in kernel mode, sig: 5 [#1]
NIP: C0029090 LR: C00290A0 SP: CCD69B20 REGS: ccd69a70 TRAP: 0700    Not tainted
MSR: 00021000 EE: 0 PR: 0 FP: 0 ME: 1 IR/DR: 00
TASK = cde58080[170] 'ifconfig' THREAD: ccd68000
Last syscall: 54
GPR00: 00000001 CCD69B20 CDE58080 C0311DD4 C031269C FFFBD700 C0311F4C C0311E94
GPR08: FFFBD869 00003B60 00000169 00003B5F FFFBD700 1010A204 00000000 00000000
GPR16: 00000000 1001C094 00000000 00000000 C07D2400 FFFF8914 C03092C0 C0310000
GPR24: C0310000 C0310000 C0280000 C0311DD4 00000017 C0311DD4 C0312694 C031269C
NIP [c0029090] cascade+0x40/0x78
LR [c00290a0] cascade+0x50/0x78
Call trace:
 [c002923c] run_timer_softirq+0x174/0x1d8
 [c0024b4c] __do_softirq+0x80/0xf4
 [c0024c18] do_softirq+0x58/0x60
 [c0003930] timer_interrupt+0xa0/0x208
 [c0002598] ret_from_except+0x0/0x18
 [c001f694] release_console_sem+0xc4/0x234
 [c001f95c] vprintk+0x158/0x1c0
 [c001fa14] printk+0x50/0x60
 [c014d91c] get_phy_info+0xcc/0xe4
 [c014b30c] gfar_enet_open+0x2ec/0x390
 [c01a7630] dev_open+0xb0/0xd8
 [c01a8dc4] dev_change_flags+0x6c/0x144
 [c01e6eec] devinet_ioctl+0x618/0x764
 [c01e8250] inet_ioctl+0x10c/0x120
 [c019dbcc] sock_ioctl+0x1ac/0x288
Kernel panic - not syncing: Aiee, killing interrupt handler!
 <0>Rebooting in 1 seconds..U-Boot 1.1.2 (Aug 19 2005 - 09:55:23)
-------------- next part --------------
A non-text attachment was scrubbed...
Name: fixIFCONFIGpanic.patch
Type: application/octet-stream
Size: 1677 bytes
Desc: not available
Url : http://ozlabs.org/pipermail/linuxppc-embedded/attachments/20050929/3185a7c9/attachment.obj 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: net_setting.sh
Type: application/octet-stream
Size: 291 bytes
Desc: not available
Url : http://ozlabs.org/pipermail/linuxppc-embedded/attachments/20050929/3185a7c9/attachment-0001.obj