[FYI] Remove obsolete assertion from regcache.c

[Tom Tromey <tom@tromey.com>]

When building I got:

../../binutils-gdb/gdb/regcache.c:935:24: error: the address of ‘ssize_t read(int, void*, size_t)’ will never be NULL [-Werror=address]

This happens because "read" used to be a parameter to this function,
which was then removed; but the assertion wasn't updated.

I don't think the assertion is relevant any more, to this removes it.
I'm checking it in as obvious.

2017-10-17  Tom Tromey  <tom@tromey.com>

	* regcache.c (enum register_status): Remove assertion.
---
 gdb/ChangeLog  | 4 ++++
 gdb/regcache.c | 1 -
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 65952c4..8931f36 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2017-10-17  Tom Tromey  <tom@tromey.com>
+
+	* regcache.c (enum register_status): Remove assertion.
+
 2017-10-17  Pedro Alves  <palves@redhat.com>
 
 	* xml-support.c (xml_fetch_content_from_file): Call
diff --git a/gdb/regcache.c b/gdb/regcache.c
index 555db57..603d2f2 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -932,7 +932,6 @@ regcache::xfer_part (int regnum, int offset, int len, void *in,
     {
       enum register_status status;
 
-      gdb_assert (read != NULL);
       if (is_raw)
 	status = raw_read (regnum, reg);
       else
-- 
2.9.5