[PATCH v4 1/5] pstore: use snprintf

No guarantees that the names will not exceed the
name buffer with future adjustments.

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Acked-by: Joe Perches <joe@perches.com>

v2: switch from snprintf to scnprintf
v3: remove embedded space
v4: renumber pmsg series dependencies

Change-Id: I161fe8cadc967d74e18cc09b7d60b5b398c92c86