nvgpu: fix railgate_enable_store

Writing same value to railgate_enable_store should be treated as nop
and made successfully. Doing so is not only an optimization for the
operation but also convention that users expect for "settings". This
change is primary for fixing a peculiar situation in the driver:

root@localhost:/sys/devices/17000000.gp10b# cat railgate_enable
0
root@localhost:/sys/devices/17000000.gp10b# echo 0 > railgate_enable
bash: echo: write error: Invalid argument

Attempt to disable railgating on a platform where railgating isn't
supported shouldn't be treated as 'invalid'. It's disabled after all.

Bug 200562094

Change-Id: I3c04934bdbaf337c33d7de9cac6d53c96b4dacae
Signed-off-by: Leon Yu <leoyu@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2225476
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Debarshi Dutta <ddutta@nvidia.com>
Reviewed-by: Bibek Basu <bbasu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

0 files changed, 0 insertions, 0 deletions