Not strictly speaking a lfsr, but here's some el cheapo prng for ya:

  clc

state_lo:

  lda #0

  adc #$57

  sta state_lo+1

state_hi:

  lda #0

  adc #$21

  clc

  rol

  adc #1

  sta state_hi+1

On VCS you'd have to use some zp location, ofc.

i'm confused:: why are you stashing the accumulator into the lda neumonic? (state_lo+1 and state_hi+1)
maybe i don't understand your compiler

it's stashed into the immediate value that follows the lda. so after the first round, it'll be

state_lo:

  lda #$57

  ...

You can use other values instead of $57/$21 btw, but not all values work equally well.

err, did that answer your question, actually?