file.c: the "rb" os_fopen() flags are static in two places, simplify
file.c: the "rb" os_fopen() flags are static in two places, simplify

We can still allocate these as a static array, just not a static
string.

Signed-off-by: H. Peter Anvin (Intel) <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>

techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm,techkey/nasm