gdb: provide and use sparc{32,64} target description XML files.

gdb/ChangeLog:

2017-02-06  Ivo Raisr  <ivo.raisr@oracle.com>

	PR tdep/20936
	Provide and use sparc32 and sparc64 target description XML files.
	* features/sparc/sparc32-cp0.xml, features/sparc/sparc32-cpu.xml,
	features/sparc/sparc32-fpu.xml: New files for sparc 32-bit.
	* features/sparc/sparc64-cp0.xml, features/sparc/sparc64-cpu.xml,
	features/sparc/sparc64-fpu.xml: New files for sparc 64-bit.
	* features/sparc/sparc32-solaris.xml: New file.
	* features/sparc/sparc64-solaris.xml: New file.
	* features/sparc/sparc32-solaris.c: Generated.
	* features/sparc/sparc64-solaris.c: Generated.
	* sparc-tdep.h: Account for differences in target descriptions.
	* sparc-tdep.c (sparc32_register_name): Use target provided registers.
	(sparc32_register_type): Use target provided registers.
	(validate_tdesc_registers): New function.
	(sparc32_gdbarch_init): Use tdesc_has_registers.
	Set pseudoregister functions.
	* sparc64-tdep.c (sparc64_register_name): Use target provided registers.
	(sparc64_register_type): Use target provided registers.
	(sparc64_init_abi): Set pseudoregister functions.

gdb/doc/ChangeLog:

2017-02-06  Ivo Raisr  <ivo.raisr@oracle.com>

	PR tdep/20936
	* gdb.texinfo: (Standard Target Features): Document SPARC features.
	(Sparc Features): New node.

gdb/testsuite/ChangeLog:

2017-02-06  Ivo Raisr  <ivo.raisr@oracle.com>

	PR tdep/20936
	* gdb.xml/tdesc-regs.exp: Provide sparc core registers for the tests.