Allow specifying PIO/SM number for "assemble"

[kuba2k2]

This PR makes it possible to specify PIO/SM number when using the assemble command for loading PIO programs, without having to manually configure wrap/side-set configuration.

Example of loading two single-instruction programs to SM 0/1/2/3 from a single PIO file:

> assemble -i prog.pio +l -P sample_in -p 0 -s 0
pioasm exited with code 0
parsed program "sample_in" with 1 PIO SM instructions
(pio0:sm*) loaded program sample_in at address 0x00
(pio0:sm0) set wrap=0
(pio0:sm0) set wrap_target=0
(pio0:sm0) set side-set count to 0
(pio0:sm0) set side-set opt=false
(pio0:sm0) set side-set pindirs=false
> assemble -i prog.pio +l -P sample_in -p 0 -s 1
pioasm exited with code 0
parsed program "sample_in" with 1 PIO SM instructions
(pio0:sm*) loaded program sample_in at address 0x01
(pio0:sm1) set wrap=1
(pio0:sm1) set wrap_target=1
(pio0:sm1) set side-set count to 0
(pio0:sm1) set side-set opt=false
(pio0:sm1) set side-set pindirs=false
> assemble -i prog.pio +l -P sample_out -p 0 -s 2
pioasm exited with code 0
parsed program "sample_out" with 1 PIO SM instructions
(pio0:sm*) loaded program sample_out at address 0x02
(pio0:sm2) set wrap=2
(pio0:sm2) set wrap_target=2
(pio0:sm2) set side-set count to 0
(pio0:sm2) set side-set opt=false
(pio0:sm2) set side-set pindirs=false
> assemble -i prog.pio +l -P sample_out -p 0 -s 3
pioasm exited with code 0
parsed program "sample_out" with 1 PIO SM instructions
(pio0:sm*) loaded program sample_out at address 0x03
(pio0:sm3) set wrap=3
(pio0:sm3) set wrap_target=3
(pio0:sm3) set side-set count to 0
(pio0:sm3) set side-set opt=false
(pio0:sm3) set side-set pindirs=false

Notice how the wrap/wrap target addresses are now relative to the just-loaded program's start address.

[kuba2k2]

Also added automatic relocation of jmp target addresses when the program is loaded at a non-zero address (the pico-sdk does that too).