Add support for soft-float mips

[guyush1]

see #51

[roddyrap]

@guyush1 do you need to make changes or recompile the musl-cross-compiler to compile sf?

[guyush1]

I need to add configuratuons for the new architectures and then compile & upload them so we can download them here

[roddyrap]

Do we want to rebase the compilers on upstream?

[guyush1]

no, we are still on the latest tag in musl-cross-make

[guyush1]

tasks:

• Compile & upload mips-sf & mipsel-sf musl compilers
• Add targets to gdb scripts, compile them and check