The NEON-optimised implementation of memchr has a couple of minor issues - it
does not mask off the higher bits of the input character, and it uses a signed
comparison instead of unsigned within the smallstr loop. This patch addresses
both of these issues.

ChangeLog:

2017-06-02  Prakhar Bahuguna  <prakhar.bahuguna@arm.com>

	* libc/machine/arm/memchr.S: Add and instruction to mask off all but
	the lowest byte.
	Change blt to blo.

Okay for master?

-- 

Prakhar Bahuguna