Fix build for mingw32 on windows ($$ expansion)
Make using mingw32 on windows fails when running grep "=y$$".
The command is expanded to grep "=y$ and the missing "
results in an error.
I don't expect a file config-devices.mak with =y somewhere in
the middle of a line (they are always at the end of the line),
so simplifying the regular expression to =y seems to be permitted.
This avoids problems with wrong expansion.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>