drm/amdgpu: some improvement in parsing inputs

It changes the way to skip newline character and also avoids
warning message from some compiler.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Eric Huang <JinHuiEric.Huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c

@@ -365,7 +365,9 @@ static ssize_t amdgpu_set_pp_dpm_sclk(struct device *dev,
 	uint32_t i, mask = 0;
 	char sub_str[2];
 
-	for (i = 0; i < strlen(buf) - 1; i++) {
+	for (i = 0; i < strlen(buf); i++) {
+		if (*(buf + i) == '\n')
+			continue;
 		sub_str[0] = *(buf + i);
 		sub_str[1] = '\0';
 		ret = kstrtol(sub_str, 0, &level);
@@ -413,7 +415,9 @@ static ssize_t amdgpu_set_pp_dpm_mclk(struct device *dev,
 	uint32_t i, mask = 0;
 	char sub_str[2];
 
-	for (i = 0; i < strlen(buf) - 1; i++) {
+	for (i = 0; i < strlen(buf); i++) {
+		if (*(buf + i) == '\n')
+			continue;
 		sub_str[0] = *(buf + i);
 		sub_str[1] = '\0';
 		ret = kstrtol(sub_str, 0, &level);
@@ -461,7 +465,9 @@ static ssize_t amdgpu_set_pp_dpm_pcie(struct device *dev,
 	uint32_t i, mask = 0;
 	char sub_str[2];
 
-	for (i = 0; i < strlen(buf) - 1; i++) {
+	for (i = 0; i < strlen(buf); i++) {
+		if (*(buf + i) == '\n')
+			continue;
 		sub_str[0] = *(buf + i);
 		sub_str[1] = '\0';
 		ret = kstrtol(sub_str, 0, &level);