gdbserver: make linux target op 'cannot_store_register' a predicate function

The comment for the linux target op 'cannot_store_register' states the
following:

  /* Returns 0 if we can store the register, 1 if we can not
     store the register, and 2 if failure to store the register
     is acceptable.  */

There is only one low target, linux-ppc-low, that potentially returns
2.  There are two places that call the 'cannot_store_register' target
op in linux-low.cc.  None of these locations distinguish a '2' from a
'1'.  Hence, to simplify the definition, make the function a predicate
that returns either 0 or 1.  This is also consistent with the
companion function, 'cannot_fetch_register'.

gdbserver/ChangeLog:
2020-04-02  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* linux-low.h (struct linux_target_ops): Update the comment for
	'cannot_store_register' to return 0 or 1.
	* linux-ppc-low.cc (ppc_cannot_store_register): Return 1 instead
	of 2.

1 files changed, 2 insertions, 2 deletions

diff --git a/gdbserver/linux-ppc-low.cc b/gdbserver/linux-ppc-low.cc
index fd6d0369c48..f3837e47960 100644
--- a/gdbserver/linux-ppc-low.cc
+++ b/gdbserver/linux-ppc-low.cc
@@ -152,13 +152,13 @@ ppc_cannot_store_register (int regno)
   /* Some kernels do not allow us to store fpscr.  */
   if (!(ppc_hwcap & PPC_FEATURE_HAS_SPE)
       && regno == find_regno (tdesc, "fpscr"))
-    return 2;
+    return 1;
 #endif
 
   /* Some kernels do not allow us to store orig_r3 or trap.  */
   if (regno == find_regno (tdesc, "orig_r3")
       || regno == find_regno (tdesc, "trap"))
-    return 2;
+    return 1;
 
   return 0;
 }