qt5script: fix build issue with 32-bits armv8-a

Adds WTF platform support for the 32-bits armv8-a architectures.

Fixes:

	In file included from ../3rdparty/javascriptcore/JavaScriptCore/config.h:26,
	                from ../3rdparty/javascriptcore/JavaScriptCore/pcre/pcre_compile.cpp:44:
	../3rdparty/javascriptcore/JavaScriptCore/wtf/Platform.h:370:6: error: #error "Not supported ARM architecture"
	#    error "Not supported ARM architecture"
	     ^~~~~

The patch is based on two upstream fixes in WebKit[1][2].

See also commit cea7aa87.

[1]: https://github.com/WebKit/webkit/commit/313d9fc4bdd2f020a5d0cf834c3c61982f161ebb
[2]: https://github.com/WebKit/webkit/commit/98f0de0709786f5d9b09dfd5908266990eb909d6



Signed-off-by: Gaël PORTAY <gael.portay@savoirfairelinux.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>