Kconfig: Make all Kconfig encoding ascii

Some of Kconfigs are using utf-8 encoding because of used chars. Convert
all of them to ascii enconging. Based on discussion ASCII should be used in
general with the exception of names.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-rockchip/rv1126/Kconfig b/arch/arm/mach-rockchip/rv1126/Kconfig
index ae323ee..330b7df 100644
--- a/arch/arm/mach-rockchip/rv1126/Kconfig
+++ b/arch/arm/mach-rockchip/rv1126/Kconfig
@@ -6,8 +6,8 @@
 	  Neu2:
 	  Neural Compute Module 2(Neu2) is a 96boards SoM-CB compute module
 	  based on Rockchip RV1126 from Edgeble AI.
-	  Neu2 powered with Consumer grade (0 to +80 °C) RV1126 SoC.
-	  Neu2k powered with Industrial grade (-40 °C to +85 °C) RV1126K SoC.
+	  Neu2 powered with Consumer grade (0 to +80 deg C) RV1126 SoC.
+	  Neu2k powered with Industrial grade (-40 C to +85 deg C) RV1126K SoC.
 
 	  Neu2-IO:
 	  Neural Compute Module 2(Neu2) IO board is an industrial form factor