fsp: Fix sparse warning
fsp: Fix sparse warning

platforms/ibm-fsp/common.c:252:17: error: symbol 'fsp_heartbeat_time' redeclared with different type (different modifiers):
platforms/ibm-fsp/common.c:252:17:    int extern [addressable] [pure] [signed] [toplevel] fsp_heartbeat_time( ... )
platforms/ibm-fsp/common.c: note: in included file:
platforms/ibm-fsp/ibm-fsp.h:40:5: note: previously declared as:
platforms/ibm-fsp/ibm-fsp.h:40:5:    int extern [addressable] [signed] [toplevel] fsp_heartbeat_time( ... )

Signed-off-by: Vasant Hegde <a6d753843573f7bfed5075c1e875b0be8007a0ab@linux.vnet.ibm.com>

legoater/skiboot,shenki/skiboot,open-power/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot,open-power/skiboot,legoater/skiboot,legoater/skiboot,qemu/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,qemu/skiboot,open-power/skiboot,qemu/skiboot