Shrink size of file so bootloader builds
Shrink size of file so bootloader builds

Remove the fixed 512 byte size of the mbed redirect file since this is
this is no longer needed.  This allows the K22F bootloader to build in
uVision 5.

google/DAPLink-port,sg-/DAPLink,google/DAPLink-port,google/DAPLink-port,sg-/DAPLink,sg-/DAPLink,google/DAPLink-port