ARM: 7385/1: ThumbEE: Use cpuid macros to read ID_PFR0 for ThumbEE

The ThumbEE probe code uses inline assembly to read ID_PFR0 in order to
detect whether ThumbEE is implemented by the processor.

This patch replaces the inline asm with the read_cpuid_ext macro.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>