Fixed some issues that prevented ipv6 to work with ipv4 enabled.

drivers/:  Remove all explicit use of 'hidden' macro _info.  Code must never use this directly.  Code must always use a debug macro such as info which is basic on _info but can be appropriately filtered.

SMP Signals: Fix some SMP signal delivery logic. Was not handling some critical sections correctly and was missing logic to signal tasks running on other CPUs.

SMP: Fix an error in critical section logic when performing a context switch from an interrupt handler.  The g_cpu_irqset bit was not being set for the CPU so other CPUs did not know about the critical section.

Merged in david_s5/nuttx/upstream_revert_265af481 (pull request #194)

Revert "STM32 serial: Make input hardware flow-control work with RX DMA.  From Jussi Kivilinna"

HSI should not be turned off

This reverts commit 4e051c05.

This change broke the STM32 seril driver.

HSI should not be turned off

STM32F4 does not have the requierment that the HSI be on for FLASH erase/write operations