gdb: Reformat amd64_dwarf_reg_to_regnum

Reformat amd64_dwarf_reg_to_regnum:

@@ -254,8 +254,7 @@ amd64_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
   if (reg >= 0 && reg < amd64_dwarf_regmap_len)
     regnum = amd64_dwarf_regmap[reg];

-  if (ymm0_regnum >= 0
-	   && i386_xmm_regnum_p (gdbarch, regnum))
+  if (ymm0_regnum >= 0 && i386_xmm_regnum_p (gdbarch, regnum))
     regnum += ymm0_regnum - I387_XMM0_REGNUM (tdep);

to remove the misaligned line.