The first IA MCU processor will be Lakemount.  This patch changes IA MCU
processor name from iamcu to lakemount.

gcc/

	* config.gcc (x86_archs): Replace iamcu with lakemount.
	(with_cpu): Likewise.
	(with_arch): Likewise.
	* doc/invoke.texi: Likewise.
	* config/i386/i386-c.c (ix86_target_macros_internal): Replace
	PROCESSOR_IAMCU with PROCESSOR_LAKEMOUNT.  Replace
	__tune_iamcu__ with __tune_lakemount__.
	* config/i386/i386.c (iamcu_cost): Renamed to ...
	(lakemount_cost): This.
	(m_IAMCU): Renamed to ...
	(m_LAKEMOUNT): This.
	(initial_ix86_arch_features): Replace m_IAMCU with m_LAKEMOUNT.
	(processor_target_table): Replace "iamcu" with "lakemount".
	(processor_alias_table): Likewise.
	(ix86_issue_rate): Replace PROCESSOR_IAMCU with
	PROCESSOR_LAKEMOUNT.
	(ix86_adjust_cost): Likewise.
	(ia32_multipass_dfa_lookahead): Likewise.
	* config/i386/i386.h (processor_type): Likewise.
	* config/i386/x86-tune.def: Replace m_IAMCU with m_LAKEMOUNT.

gcc/testsuite/

	* gcc.target/i386/pr66749.c (dg-options): Replace -mtune=iamcu
	with -mtune=lakemount.
	* gcc.target/i386/pr66821.c (dg-options): Likewise.
	* gcc.target/i386/pr67329.c (dg-options): Likewise.

From-SVN: r228109