clang-tidy: Fix bugprone-narrowing-conversion diagnostic
```
/usr/bin/clang-tidy -checks=-*, bugprone-narrowing-conversions -export-fixes /tmp/tmp9pcdq4bf/tmpulhoe1tp.yaml -p=build /mnt/host/andrew/src/openbmc/libpldm/src/requester/pldm.c
../src/requester/pldm.c:32:7: error: narrowing conversion from 'ssize_t' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions,-warnings-as-errors]
rc = write(fd, &MCTP_MSG_TYPE_PLDM, sizeof(MCTP_MSG_TYPE_PLDM));
^
```
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I95e70d4692dd57d87216e75adb9ac26ab4b96bb9
diff --git a/src/requester/pldm.c b/src/requester/pldm.c
index 8b9a17c..1dea225 100644
--- a/src/requester/pldm.c
+++ b/src/requester/pldm.c
@@ -12,8 +12,8 @@
pldm_requester_rc_t pldm_open(void)
{
+ ssize_t rc = -1;
int fd = -1;
- int rc = -1;
fd = socket(AF_UNIX, SOCK_SEQPACKET, 0);
if (-1 == fd) {