wip: Revert "ARM: omap2plus_defconfig: Enable OMAP3_THERMAL"

This reverts commit a82820f.

The commit prevents the Nokia N900 from entering OFF mode, so the
feature likely needs more work before being turned on by default.

arch/arm/configs/omap2plus_defconfig

@@ -467,7 +467,6 @@ CONFIG_THERMAL_GOV_FAIR_SHARE=y
 CONFIG_THERMAL_GOV_USER_SPACE=y
 CONFIG_CPU_THERMAL=y
 CONFIG_TI_THERMAL=y
-CONFIG_OMAP3_THERMAL=y
 CONFIG_OMAP4_THERMAL=y
 CONFIG_OMAP5_THERMAL=y
 CONFIG_DRA752_THERMAL=y