By Matt Hladik Bronny James is still only in high school, but he’s already secured his own sponsorship deal with PSD Underwear. LeBron’s son is the first high school athlete to partner with the company. Bronny’s own PSD collection will debut later this year, and his dad already plans on getting his hands on some of the products. He jokingly thanked his son “in advance” for the swag on Twitter today. “Yessir!!!! Who’s ready for the Bronny collection that’s coming with @PSDunderwear ??!!!” James wrote. “Well I know I am!! Need those ASAP son! Thank you in advance. Lol. Congrats Young.” By linkin…