treewide: Fix wrong CONFIG_IS_ENABLED() handling

CONFIG_IS_ENABLED() takes the kconfig name without the CONFIG_ prefix,
e.g. CONFIG_IS_ENABLED(CLK) for CONFIG_CLK. Some of these were being
fixed every now and then, see:

    commit 71ba2cb0 ("board: stm32mp1: correct CONFIG_IS_ENABLED usage for LED")
    commit a5ada25e ("rockchip: clk: fix wrong CONFIG_IS_ENABLED handling")
    commit 5daf6e56 ("common: console: Fix duplicated CONFIG in silent env callback")
    commit 48bfc31b ("MIPS: bootm: Fix broken boot_env_legacy codepath")

Fix all files found by `git grep "CONFIG_IS_ENABLED(CONFIG"` by running
':%s/CONFIG_IS_ENABLED(CONFIG_\(\w+\))/CONFIG_IS_ENABLED(\1)/g' in vim.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>