[ARM] 4473/2: Take the HWCAP definitions out of the elf.h file

The patch moves the HWCAP definitions and the extern elf_hwcap
declaration to the hwcap.h header file.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>