Revert "[CPUFREQ] constify cpufreq_driver where possible."

This reverts commit aeeddc1435c37fa3fc844f31d39c185b08de4158, which was
half-baked and broken.  It just resulted in compile errors, since
cpufreq_register_driver() still changes the 'driver_data' by setting
bits in the flags field.  So claiming it is 'const' _really_ doesn't
work.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
index d98529c9..837b041 100644
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
@@ -647,7 +647,7 @@
 	NULL,
 };
 
-static const struct cpufreq_driver powernow_driver = {
+static struct cpufreq_driver powernow_driver = {
 	.verify	= powernow_verify,
 	.target	= powernow_target,
 	.get	= powernow_get,