PlatformIO does not support this particular chip, but 8051 chips in general per GitHub - platformio/platform-intel_mcs51: Intel MCS-51 (8051): development platform for PlatformIO and Intel MCS-51 (8051) — PlatformIO latest documentation. The underlying compiler is the free SDCC compiler. If the TI CC253x is 8051 based, please open a feature-request issue in that Github repo.
On the other hand, ARM-type TI CC13x0 chips are supported.