I found a perfectly working code for TMs & HMs Deleter and big credit to the owner!
94000130 FCFF0000B2000024 00000000C0000000 00000062000192E0 00000000DC000000 00000004D2000000 00000000
Press L+R
Tried and tested by me and working perfectly, if it's doesn't clear your TMs & HMs Bag, just press it again to emptied it completely! By the way I'm using Pokemon White US in Desmume.