ARM: 8300/1: teach __asmeq that r11 == fp and r12 == ip

The __asmeq macro is used inside inline asm statements to ensure that
register asm variables that explicitly specify a register are mapped
correctly onto those registers when used in inline asm input and output
constraints. However, the string based matching fails to take into
account that 'fp' is often referred to as 'r11' and 'ip' is often
referred to as 'r12', (e.g., by clang), causing false negatives.

Fix this by making __asmeq consider the ("fp","r11"), ("r11","fp"),
("ip","r12") and ("r12","ip") cases specifically.

Reviewed-by: Alex Elder <elder@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>