Bode diagram for RL circuit
"How do I transform 1/jω to jω"   


You don't. Although 1/j=-j  Here you were incorrectly assuming a 1st order LPF function instead of an HPF.

LPF function \$~ \dfrac{A}{1+j(\omega / \omega_c)} \$
with HPF function  \$\dfrac{A ~j(\omega / \omega_c)}{1+j(\omega / \omega_c)} \$ 

Instead of C use ωc where \$T = 1/\omega _c = L/R_{eq}\$  .

The constant A is the R attenuation ratio which has a parallel Req value..