i386: Resolve variable shadowing in i386-options.c [PR98671]

i386: Resolve variable shadowing in i386-options.c [PR98671]

Also change global variable pta_size to unsigned.

2021-01-14  Uroš Bizjak  <ubizjak@gmail.com>

gcc/
	PR target/98671
	* config/i386/i386-options.c (ix86_valid_target_attribute_inner_p):
	Remove declaration and initialization of shadow variable "ret".
	(ix86_option_override_internal): Remove delcaration of
	shadow variable "i".  Redeclare shadowed variable to unsigned.
	* common/config/i386/i386-common.c (pta_size): Redeclare to unsigned.
	* config/i386/i386-builtins.c (get_builtin_code_for_version):
	Update for redeclaration.
	* config/i386/i386.h (pta_size): Ditto.