firmware: -nostartfiles -nodefaultlibs are not flags of LD but flags of GCC
It seems that those flags have always been gcc flags, and not ld flags.
After decades of tolerating this, binutils 2.36.x no longer tolerates
those flags but prints an error:
arm-none-eabi-ld: Error: unable to disambiguate: -nostartfiles (did you mean --nostartfiles ?)
See also https://github.com/apache/nuttx/issues/3826 and the related
https://github.com/apache/nuttx/pull/3836 how this was solved in another
project - I adopted that solution here 1:1
Change-Id: Id199e4d03d5aae07a347c98f47791f42c12008c6