move time_t and suseconds_t definitions to common alltypes.h.in

now that all 32-bit archs have 64-bit time_t (and suseconds_t), the
arch-provided _Int64 macro (long or long long, as appropriate) can be
used to define them, and arch-specific definitions are no longer
needed.

arch/powerpc/bits/alltypes.h.in

@@ -18,6 +18,3 @@ TYPEDEF float float_t;
 TYPEDEF double double_t;
 
 TYPEDEF struct { long long __ll; long double __ld; } max_align_t;
-
-TYPEDEF long long time_t;
-TYPEDEF long long suseconds_t;