c-family: Fix bootstrap for targets defining TARGET_FORMAT_TYPES.

c-family: Fix bootstrap for targets defining TARGET_FORMAT_TYPES.

A recent improvement in Waddress causes a bootstrap failure on
targets that define TARGET_FORMAT_TYPES since it cannot be NULL
if defined to an address.

There is no default for this target macro, and it would seem no
purpose to defining it to NULL, so the warning appears reasonable.

Fixed by removing the pointless test.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
gcc/c-family/ChangeLog:

	* c-format.c: Remove a test of TARGET_FORMAT_TYPES with
	NULL, this is not needed.