sw64: fix a type mismatch problem

Sunway inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I56QAM

--------------------------------

This patch fixes a pointer/integer type mismatch in conditional
expression, which leads to a compile warning.
Signed-off-by: NHe Sheng <hesheng@wxiat.com>
Reviewed-by: NCui Wei <cuiwei@wxiat.com>
Signed-off-by: NGu Zitao <guzitao@wxiat.com>

arch/sw_64/kernel/perf_regs.c

@@ -20,7 +20,7 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
 	case PERF_REG_SW64_GP:
 		return regs->gp;
 	case PERF_REG_SW64_SP:
-		return (u64)(user_mode(regs) ? rdusp() : (regs + 1));
+		return (user_mode(regs) ? rdusp() : (u64)(regs + 1));
 	case PERF_REG_SW64_PC:
 		return regs->pc;
 	default: