[Bug] Add COMPARISON_NONE; fix the error message related to it

[ModulePillow]

Description
Regarding the sampler description, I found two issues shown below. For more details, please go to the PR #8245

1. D3D12_COMPARISON_FUNC_NONE should be added; it is a valid value for the non-comparison samplers.
2. The error message should be revised; the original one shows "Unexpected texture address mode value", which is confusing.

Steps to Reproduce
cmd line: dxc -T rootsig_1_0 -E ROOT_SIGN_DUMMY -Fo PillowRS.cso -Fe errors.log ./Pillow.hlsl

Pillow.hlsl
#define ROOT_SIGN_DUMMY "RootFlags(0), " \
   "CBV(b0), " \
   "StaticSampler(s0, filter = FILTER_MIN_MAG_MIP_POINT,  comparisonFunc = COMPARISON_NONE)"

Actual Behavior
...\Pillow.hlsl:120:9: error: root signature error - Unexpected texture address mode value: 'COMPARISON_NONE'.

Environment

• dxcompiler.dll: 1.9(5184-21d28f72)(1.9.2602.17) - 1.9.2602.17 (21d28f7)
• Win 11