gdbserver: include aarch32/aarch64 header file in corresponding source file

gdbserver: include aarch32/aarch64 header file in corresponding source file

When building gdbserver for an aarch64 host with -Wmissing-declarations,
I see:

  CXX    linux-aarch32-tdesc.o
/home/simark/src/binutils-gdb/gdb/gdbserver/linux-aarch32-tdesc.c:28:1: error: no previous declaration for 'const target_desc* aarch32_linux_read_description()' [-Werror=missing-declarations]
 aarch32_linux_read_description ()
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/simark/src/binutils-gdb/gdb/gdbserver/linux-aarch32-tdesc.c:43:1: error: no previous declaration for 'bool is_aarch32_linux_description(const target_desc*)' [-Werror=missing-declarations]
 is_aarch32_linux_description (const target_desc *tdesc)
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

  CXX    linux-aarch64-tdesc.o
/home/simark/src/binutils-gdb/gdb/gdbserver/linux-aarch64-tdesc.c:32:1: error: no previous declaration for 'const target_desc* aarch64_linux_read_description(uint64_t, bool)' [-Werror=missing-declarations]
 aarch64_linux_read_description (uint64_t vq, bool pauth_p)
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix it by including linux-aarch32-tdesc.h in linux-aarch32-tdesc.c and
linux-aarch64-tdesc.h in linux-aarch64-tdesc.c.

gdb/gdbserver/ChangeLog:

	* linux-aarch32-tdesc.c: Include linux-aarch32-tdesc.h.
	* linux-aarch64-tdesc.c: Include linux-aarch64-tdesc.h.