dm: Kconfig: Move CONFIG_SYS_MALLOC_F_LEN to Kconfig

Kconfig

arch/arm/cpu/armv7/exynos/Kconfig

arch/arm/cpu/armv7/omap3/Kconfig

arch/arm/cpu/armv7/tegra-common/Kconfig

arch/arm/cpu/armv7/uniphier/Kconfig

arch/x86/Kconfig

board/ti/am335x/Kconfig

configs/Linksprite_pcDuino3_fdt_defconfig

configs/am335x_igep0033_defconfig

configs/cm_fx6_defconfig

configs/cm_t335_defconfig

configs/gwventana_defconfig

configs/mx6dlsabreauto_defconfig

configs/mx6qsabreauto_defconfig

configs/mx6qsabresd_defconfig

configs/mx6sxsabresd_defconfig

configs/nokia_rx51_defconfig

configs/pcm051_rev1_defconfig

configs/pcm051_rev3_defconfig

configs/pengwyn_defconfig