remove spl-math from stake-pool deps (it was already unused)

Author: kevinheavey

Cargo.lock

@@ -22,9 +22,6 @@ serde = "1.0.214"
 serde_derive = "1.0.103"
 solana-program = "2.1.0"
 solana-security-txt = "1.1.1"
-spl-math = { version = "0.3", path = "../../libraries/math", features = [
-  "no-entrypoint",
-] }
 spl-pod = { version = "0.4.0", path = "../../libraries/pod", features = [
   "borsh",
 ] }