[RISCV][NFC] Update RISCVInstrInfoC.td to match usual instruction naming convention

When an instruction mnemonic contains a '.', we usually name the instruction
with a _ in that place. e.g. fadd.s -> FADD_S.

This patch updates RISCVInstrInfoC.td to do the same, e.g. c.nop -> C_NOP.

Also includes some minor formatting changes in RISCVInstrInfoC.td to better
align it with the formatting conventions in the rest of the backend.

llvm-svn: 320560
diff --git a/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp b/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
index 932bc71..563edc9 100644
--- a/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
+++ b/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
@@ -186,14 +186,16 @@
 // Add implied SP operand for instructions *SP compressed instructions. The SP
 // operand isn't explicitly encoded in the instruction.
 static void addImplySP(MCInst &Inst, int64_t Address, const void *Decoder) {
-  if (Inst.getOpcode() == RISCV::CLWSP || Inst.getOpcode() == RISCV::CSWSP ||
-      Inst.getOpcode() == RISCV::CLDSP || Inst.getOpcode() == RISCV::CSDSP ||
-      Inst.getOpcode() == RISCV::CFLWSP || Inst.getOpcode() == RISCV::CFSWSP ||
-      Inst.getOpcode() == RISCV::CFLDSP || Inst.getOpcode() == RISCV::CFSDSP ||
-      Inst.getOpcode() == RISCV::CADDI4SPN) {
+  if (Inst.getOpcode() == RISCV::C_LWSP || Inst.getOpcode() == RISCV::C_SWSP ||
+      Inst.getOpcode() == RISCV::C_LDSP || Inst.getOpcode() == RISCV::C_SDSP ||
+      Inst.getOpcode() == RISCV::C_FLWSP ||
+      Inst.getOpcode() == RISCV::C_FSWSP ||
+      Inst.getOpcode() == RISCV::C_FLDSP ||
+      Inst.getOpcode() == RISCV::C_FSDSP ||
+      Inst.getOpcode() == RISCV::C_ADDI4SPN) {
     DecodeGPRRegisterClass(Inst, 2, Address, Decoder);
   }
-  if (Inst.getOpcode() == RISCV::CADDI16SP) {
+  if (Inst.getOpcode() == RISCV::C_ADDI16SP) {
     DecodeGPRRegisterClass(Inst, 2, Address, Decoder);
     DecodeGPRRegisterClass(Inst, 2, Address, Decoder);
   }