x86/oprofile: Fix cast of counter value

When casting the counter value to a 64 bit value in 32 bit mode, sign
extension may lead to broken counter values. This patch fixes this by
casting to (u64) instead of (s64).

Signed-off-by: Robert Richter <robert.richter@amd.com>
diff --git a/arch/x86/oprofile/op_model_p4.c b/arch/x86/oprofile/op_model_p4.c
index f01e53b..9db9e36 100644
--- a/arch/x86/oprofile/op_model_p4.c
+++ b/arch/x86/oprofile/op_model_p4.c
@@ -580,7 +580,7 @@
 			reset_value[i] = counter_config[i].count;
 			pmc_setup_one_p4_counter(i);
 			wrmsrl(p4_counters[VIRT_CTR(stag, i)].counter_address,
-			       -(s64)counter_config[i].count);
+			       -(u64)counter_config[i].count);
 		} else {
 			reset_value[i] = 0;
 		}
@@ -625,11 +625,11 @@
 		if (CCCR_OVF_P(low) || !(ctr & OP_CTR_OVERFLOW)) {
 			oprofile_add_sample(regs, i);
 			wrmsrl(p4_counters[real].counter_address,
-			       -(s64)reset_value[i]);
+			       -(u64)reset_value[i]);
 			CCCR_CLEAR_OVF(low);
 			wrmsr(p4_counters[real].cccr_address, low, high);
 			wrmsrl(p4_counters[real].counter_address,
-			       -(s64)reset_value[i]);
+			       -(u64)reset_value[i]);
 		}
 	}