[RISCV] Fix TLSDESC comment. NFC (#79403)

Fix comment typos in #66915, and relocation type names related to the
example in the psABI
(riscv-non-isa/riscv-elf-psabi-doc#420).

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -6956,8 +6956,8 @@ SDValue RISCVTargetLowering::getTLSDescAddr(GlobalAddressSDNode *N,
   // This generates the pattern (PseudoLA_TLSDESC sym), which expands to
   //
   // auipc tX, %tlsdesc_hi(symbol)         // R_RISCV_TLSDESC_HI20(symbol)
-  // lw    tY, tX, %tlsdesc_lo_load(label) // R_RISCV_TLSDESC_LOAD_LO12_I(label)
-  // addi  a0, tX, %tlsdesc_lo_add(label)  // R_RISCV_TLSDESC_ADD_LO12_I(label)
+  // lw    tY, tX, %tlsdesc_load_lo(label) // R_RISCV_TLSDESC_LOAD_LO12(label)
+  // addi  a0, tX, %tlsdesc_add_lo(label)  // R_RISCV_TLSDESC_ADD_LO12(label)
   // jalr  t0, tY                          // R_RISCV_TLSDESC_CALL(label)
   SDValue Addr = DAG.getTargetGlobalAddress(GV, DL, Ty, 0, 0);
   return SDValue(DAG.getMachineNode(RISCV::PseudoLA_TLSDESC, DL, Ty, Addr), 0);