configs/stm32f4discovery:  Building of stm32_appinit.c should not depend on CONFIG_NSH_LIBRARY but on CONFIG_LIB_BOARDCTL.

configs/stm32f4discover/posix_spawn:  With recent changes, needs to enabled boardctl() w/symbol table support.

libc/lzf:  lzf_compress() now expects the hash table as user allocated input parmeter rather than declaring the huge array on the stack.

(cherry picked from commit ea77dfafe1afe7d399e47871d2ec81fea99626cc)

(cherry picked from commit 8879116fe85558520c4811dc4ab780b28e66810d)

drivers/serial/Kconfig:  Kconfig is too big, divide into Kconfig, Kconfig-uart, Kconfig-usart, Kconfig-sci, Kconfig-16550.  More than one MCU supports LPUARTs.  Add Kconfig-lpuart and remove MCU-specific LPUART definitions.  Affects Kinetis and STM32L4.