Correct #if to #ifdef when the macro can be undefined.  Fix bug in AT24XX driver:  it should compare AT24XX_ADDRSIZE to 2.

Correct #if to #ifdef when the macro can be undefined.  Fix bug in AT24XX driver:  it should compare AT24XX_ADDRSIZE to 2.

libc/math/lib_asin.c: The function did not convert for some input values.  Asin did not convert for values which do not belong to the domain of the function. But aside of that the function also did not convert for sine allowed values.  I achieved a conversion of the function by reducing the DBL_EPSION and by checking if the input value is in the domain of the function. This is a fix for the problem but the function should always terminate after a given number of iterations.  From Stefan Kolb.

fs/romfs: One allocation was not being freed if there was a subsequent failure to allocation I/O buffers resulting in a memory leak on certain error conditions.  From Bruno Herrera.

Move MTD ioctls commands from include/nuttx/fs/fs.h to include/nuttx/mtd/mtd.h.  Add commands to protect and unprotect memory

Add SSD1351 OLED controller support

net/socket and net/tcp: Fix a problem in whent there are multiple network devices.  Polls were being sent to all TCP sockets before.  This is not good because it means that packets may sometimes be sent out on the wrong device.  That is inefficient because it   will cause retransmissions and bad performance.  But, worse, when one of the devices is not Ethernet, it will have a different MSS and, as a result, incorrect data transfers can cause crashes.  The fix is to lock into a single device once the MSS is locked locked down.

Networking: Get rid of the tcp_mss macro.  It is confusing and only obfuscates what is really going on

Local loopback:  Set the IFF_UP flags during initialization because the local loopback device is always up

Networking:  Fix network device name assignment logic for the case of the local loopback device.  There is only one local loopback network device and it is unnumbered

Compilation warning fixup

Signed-off-by: Anton D. Kachalov <mouse@yandex-team.ru>