[arm] Improve error checking in parsecpu.awk

[arm] Improve error checking in parsecpu.awk

This patch adds a bit more error checking to parsecpu.awk to ensure
that statements are not missing arguments or have excess arguments
beyond those permitted.  It also slightly improves the handling of
errors so that we terminate properly if parsing fails and be as
helpful as we can while in the parsing phase.

	* config/arm/parsecpu.awk (fatal): Note that we've encountered an
	error.  Only quit immediately if parsing is complete.
	(BEGIN): Initialize fatal_err and parse_done.
	(begin fpu, end fpu): Check number of arguments.
	(begin arch, end arch): Likewise.
	(begin cpu, end cpu): Likewise.
	(cname, tune for, tune flags, architecture, fpu, option): Likewise.
	(optalias): Likewise.

From-SVN: r251800